Porsche 911 GT3 991 – Where Motorsport Meets the Road
Few badges carry the same weight as GT3. In the 991 generation, Porsche distilled decades of endurance racing into a road car that thrives on revs, precision, and feedback. The naturally aspirated flat-six, race-bred chassis geometry, and uncompromising aero make the 911 GT3 991 a benchmark for track days and fast road driving. It’s a car that rewards skill—and responds dramatically to the right upgrades.
At ATOMIC-SHOP, we curate components that enhance this platform without diluting its character: headers and cat-back exhausts, motorsport brake packages, FIA seats and harnesses, radiators and oil cooling, intakes, suspension kits, and more. Every part in our catalog is selected to add performance, consistency, and driver confidence.
Air Intake Systems for Porsche 911 GT3 991 – Breathing Clean, Breathing Cold
High rpm engines live and die by airflow quality. Even on a GT3, optimizing intake path and filtration can sharpen throttle response and stabilize power in heat. Our performance air intake systems and high-flow filters reduce restriction while keeping filtration efficiency at motorsport standards. On track, where ambient temps and heat soak rise, a more efficient inlet can keep lap-after-lap output consistent.
- Low-restriction filters that preserve MAF/MAP stability and sealing integrity.
- Smoothed intake tracts to reduce turbulence and improve cylinder fill at high rpm.
- Serviceable elements for long-term performance and predictable maintenance intervals.
For owners running frequent track sessions, a properly engineered intake helps the engine maintain its razor-sharp character across long stints—without compromising reliability.
Exhaust Systems – Headers, Manifolds & Cat-Backs That Free the Flat-Six
Exhaust tuning is the most transformative upgrade on the 991 GT3. Racing headers/exhaust manifolds paired with high-efficiency catalysts and a cat-back system reduce backpressure and improve scavenging, allowing the NA engine to breathe at high rpm. The result: crisper response, stronger mid-to-top pull, and that unmistakable GT3 timbre—now more urgent and defined.
- Headers/Exhaust manifolds: optimized primary lengths and collectors for high-rpm cylinder evacuation.
- High-flow catalysts & link pipes: power gains without excessive resonance; track-focused options available.
- Cat-back systems: weight reduction, durable stainless/titanium construction, and refined sound control.
- Exhaust accessories: clamps, mounts, valve controllers, and heat-management hardware for reliable installs.
Well-matched exhaust components don’t just add noise—they extract meaningful performance while lowering system mass and improving thermal robustness for repeated hot laps.
Brake Packages – Repeatable Stopping Power Lap After Lap
The GT3’s braking system is formidable, but repeated high-speed deceleration exposes any weak link. Our catalog includes track-compound brake pads, lightweight rotors, and braided brake lines to deliver stable bite, pedal consistency, and heat management under the harshest conditions.
- Pads (street/track compounds): predictable μ curve, low taper wear, and strong high-temp control.
- Rotors: directional vanes, optimized mass for faster cooldowns, and reduced unsprung weight.
- Braided lines: firmer pedal, reduced expansion, and precise modulation in the threshold zone.
Upgrading friction and heat pathways means later braking points, cleaner trail-brake transitions, and confidence that lasts beyond the first session of the day.
Suspension Kits & Chassis Control – Precision You Can Feel
Chassis tuning is where a GT3 truly comes alive. Our suspension kits for the 991 platform balance lap-time-focused geometry with real-road compliance. Height, rebound, and compression adjustability let you tailor turn-in, mid-corner balance, and traction on exit. We complement dampers with helper/tender springs, adjustable top mounts, and strut/power braces to lock geometry under load.
- Track-ready coilovers: multi-way adjustability for nuanced balance on slicks or semi-slicks.
- Chassis braces: reduced flex, more consistent alignment under high lateral g.
- Nose-lift/“air spring” support: clearance aids and integration parts for paddock and street use.
The goal isn’t harshness; it’s control. With a correct setup, the GT3 communicates earlier, grips longer, and rotates predictably—session after session.
Seats, Harnesses & FIA Interior – Driver Integration at Racing Spec
Fast drivers prioritize seating and restraint. We offer FIA-approved bucket seats, 4- and 6-point harnesses, and model-specific seat brackets for the 991 GT3. Proper ergonomics lock the driver’s hips and shoulders, freeing hands and feet for fine inputs—critical for managing trail brake and throttle oversteer on slick surfaces.
- FIA seats: lightweight shells, energy-absorbing foam, and lateral containment for endurance stints.
- Harnesses (4p/6p): HANS-compatible layouts, rotary cam locks, and quick-adjust hardware.
- Brackets & accessories: plug-and-play fitment, low seating position, and OEM sensor integration.
A secure seating position multiplies consistency and reduces fatigue—one of the smartest “lap time per euro” investments.
Cooling & Reliability – Radiators, Oil Systems, Transmission Care
Track heat is relentless. To keep performance intact, we stock high-efficiency radiators, ducting and accessories, plus oil cooling upgrades and transmission care solutions where applicable. Combined with motorsport-grade oils & fluids, these components protect bearings, seals, and clutches during extended stints and hot ambient conditions.
- Radiators & accessories: improved core density and airflow management.
- Oil cooling: stable viscosity and pressure when revs and temperatures climb.
- Transmission support: thermal stability for consistent shift quality across sessions.
Reliability upgrades don’t add dyno numbers—but they preserve them when it matters: the last lap of the day.
Clutch & Driveline Components – Engagement, Durability, Precision
Even in a platform optimized by the factory, driveline components benefit from race-grade materials and smart service parts. Our clutch kits and ancillary hardware (where relevant to your specification) prioritize heat tolerance, engagement feel, and durability. Pair them with correct fluids and regular inspection intervals for trouble-free high-intensity use.
- Performance clutch components: improved friction stability under repeated launches.
- Hardware & bearings: service items chosen for endurance conditions.
- Fluids: shear-stable formulas for gearbox and differential longevity.
A tidy driveline doesn’t make headlines—but it lets you focus on braking points and apexes, not “what’s that noise?”.
Aerodynamics & Diffusers – Stability That Builds Confidence
Beyond raw downforce, thoughtful aero on the 991 GT3 is about balance and repeatability. We supply diffusers and select aero accessories that tidy up the wake and reduce lift, supporting a stable platform through high-speed sweepers and heavy braking zones.
- Rear diffusers: cleaner underbody flow, better stability in crosswinds and over crests.
- Complementary pieces: grills, shields, and trimming hardware for robust installs.
- Exhaust heat-aware designs: materials and geometry that withstand track temperatures.
The payoff is a car that feels planted and trustworthy—exactly what you want when committing to fourth-gear entries.
COBB & Electronics – Calibration Tools Where Applicable
Electronics support the mechanical package. For applications where it’s appropriate, we list COBB solutions and related accessories to monitor parameters, log sessions, and coordinate minor calibrations. Used properly, data turns guesswork into progress and helps verify that each hardware change delivers the intended effect.
- Data logging: track trends in temps, fuel trims, and ignition behavior.
- Dash integration & cabling: reliable connections in high-vibration environments.
- Setup repeatability: document baselines for different tracks and conditions.
Think of electronics as your engineer’s notebook: objective, repeatable, invaluable.
Hardware, Accessories & Exhaust Fittings – The Small Things That Win Days
Most trackday delays come from “small parts.” Our accessories & hardware range covers clamps, gaskets, mounts, sensor extensions, and heat protection—everything that ensures an upgrade survives heat cycles, vibration, and curb strikes.
- Exhaust accessories: leak-free joints, valve control, and resilient hangers.
- Heat management: wraps, shields, and reflective materials around hot-side hardware.
- Service parts: quality consumables for pit-lane fixes and preventative maintenance.
Finish your build with the right “little” parts—and your big parts will keep shining.
Why Build Your Porsche 911 GT3 991 with ATOMIC-SHOP?
Because a GT3 deserves parts that respect its purpose. We source from brands proven in endurance, sprint, and club racing, we verify fitment for the 991 platform, and we back it with knowledgeable support. From a first brake upgrade to a full track package, we help you plan a coherent path that preserves drivability while raising the ceiling on performance.
- Curated catalog: headers to harnesses, radiators to rotors—platform-ready.
- Verified fitment & guidance: reduce guesswork, maximize seat time.
- EU-wide fast delivery: parts at your door before the next trackday.
- Motorsport mindset: we value repeatability, safety, and data-driven gains.
Built for Pace, Tuned for Consistency
The Porsche 911 GT3 (991) is a rare combination of purity and pace. With the right set of upgrades—breathing, flow, friction, cooling, and control—it becomes a tool that’s faster, calmer, and kinder to consumables over a full day at the circuit. Explore the ATOMIC-SHOP collection and build a GT3 that feels fresh on the last lap, not just the first.