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GR Yaris Specialists
A complete range of upgrades, all tested, developed and proven on our own GR Yaris
String Theory Signature Seats
Designed to Match OEM Interior but Improve Seating Position
Premium Exhaust Systems for Performance Cars. Stocked and fitting available with String Theory Garage
Free Fitting on GR Yaris HKS Exhausts
MILLTEK - BLACK FRIDAY SALE 20% OFF
Our Black Friday deals run from 22/11/2025 to 07/12/2025. Once it’s over, it’s over — so grab your upgrades while the offer lasts!
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Milltek Secondary Cat Bypass Exhaust System for Porsche Cayenne 958 S 4.8 V8 (Non Turbo)
Regular price £361.92 GBPRegular priceSale price £361.92 GBP -
Milltek Rear Silencer Cup Exhaust System for Porsche 911 (997.1) Carrera / Carrera S
Regular price £1,768.13 GBPRegular priceSale price £1,768.13 GBP -
Milltek OPF Back Exhaust System for Porsche 911 (992.1) Carrera S (3.0L T), GTS & Dakar OPF Models
Regular price £2,496.00 GBPRegular priceSale price £2,496.00 GBP -
Milltek Rear Silencer Exhaust System Valved for Porsche Macan 2.9 V6 GTS & Turbo (Facelift Models Only)
Regular price From £3,107.08 GBPRegular priceSale price From £3,107.08 GBP
Popular GR Yaris Upgrades
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Toyota GR Yaris Front Brake Cooling Ducts - Pair
Regular price £200.00 GBPRegular priceSale price £200.00 GBP -
STG GR Yaris 21.5mm Bolt-on Spacers (Set of 4)
Regular price £289.95 GBPRegular priceSale price £289.95 GBP -
AST 4100 Toyota GR Yaris Coilover Suspension Kit (String Theory Signature Series)
Regular price From £2,590.00 GBPRegular price£2,659.20 GBPSale price From £2,590.00 GBPSale -
STG Chassis Package - GR Yaris Gen 1
Regular price £3,850.00 GBPRegular price£4,088.37 GBPSale price £3,850.00 GBPSale
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CARGRAPHIC Porsche Exhaust Valve Control Units - Now in Stock
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Cargraphic Exhaust Valve Controller for Porsche 718 Boxster GTS (4.0L) | Spyder | RS
Regular price From £330.00 GBPRegular price£380.00 GBPSale price From £330.00 GBPSale -
Cargraphic Exhaust Valve Controller for Porsche 911 (992) GTS | GTS 4 | Targa 4 GTS (3.0L)
Regular price From £699.00 GBPRegular priceSale price From £699.00 GBP -
Cargraphic Exhaust Valve Controller for Porsche 718 Boxster GTS 4.0 | Spyder (Factory PSE Controlled)
Regular price £699.00 GBPRegular priceSale price £699.00 GBP -
Cargraphic Exhaust Valve Controller for Porsche 911 (992) Targa 4 | Targa 4S (3.0L)
Regular price From £699.00 GBPRegular priceSale price From £699.00 GBP
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Porsche Chassis Tuning Experts
String Theory Garage alignment products, upgrades and expertise help you to get the most from your Porsche's chassis.
Porsche Upgrades and Tuning Parts
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STG Titanium Exhaust Manifold Stud Kit - 911 991 GT3
Regular price £139.00 GBPRegular priceSale price £139.00 GBP -
AST Suspension 5100 Competition 1-way Adjustable Inverted Coilovers - Porsche 718 (982) Cayman | Boxster
Regular price £3,750.00 GBPRegular price£3,900.00 GBPSale price £3,750.00 GBPSale -
STG 996 / 997 Rear Dogbone Spherical Bearing Kit
Regular price £550.00 GBPRegular priceSale price £550.00 GBP -
STG Adjustable Rear Toe Link Arms - Cup Car Style 981 718
Regular price £405.00 GBPRegular priceSale price £405.00 GBP
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String Theory Garage
STG 718 Spyder/GT4 & 981 GT4 Chassis Setup
Regular price
£429.00 GBP
Regular price
Sale price
£429.00 GBP

Shop Akrapovic Exhausts
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Porsche 981 Cayman / Boxster / S / GTS | Akrapovic | Slip-On Line (Titanium)
Regular price £6,143.46 GBPRegular priceSale price £6,143.46 GBP -
Porsche 911 GT3 RS / Speedster (991.2) - OPF/GPF | Akrapovic | Race Line (Titanium)
Regular price £13,430.05 GBPRegular priceSale price £13,430.05 GBP -
Porsche 911 GT3 / GT3 Touring (991.2) | Akrapovic | Slip-On Race Line (Titanium)
Regular price £3,848.86 GBPRegular priceSale price £3,848.86 GBP -
Porsche 911 GT3 RS (991.2) | Akrapovic | Slip-On Race Line (Titanium)
Regular price £3,848.86 GBPRegular priceSale price £3,848.86 GBP
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