2005 Porsche Boxster GTS Parts: A Complete Guide to Upgrades and Restoration

If you own a 2005 Porsche Boxster and are looking for "GTS" parts, you’ve likely noticed that Porsche didn’t actually produce a Boxster GTS model that year. The GTS badge appeared on later Boxsters (2012 and newer). However, that doesn’t mean you can’t build a 2005 Boxster with GTS-level performance and style. Whether you’re restoring a salvage car, upgrading an existing Boxster, or simply searching for the right components, this guide covers the essential parts you need to transform or maintain a 2005 Boxster with a GTS spirit. We’ll focus on suspension, brakes, engine, exhaust, interior, and exterior parts that match the GTS philosophy: sharper handling, more power, and a sportier appearance.

Understanding the 2005 Boxster vs. the GTS Package

The 2005 Porsche Boxster (987 generation) came with either a 2.7L or 3.2L engine (Boxster S). The GTS that debuted in 2012 had a 3.4L engine, lower suspension, upgraded brakes, and unique styling. Since factory GTS parts from later years aren’t direct bolt-ons for the 2005 model, you’ll need aftermarket or crossover parts to achieve a similar setup. This article helps you identify which parts are interchangeable and which require modifications.

Engine Parts: Boosting Power to GTS Levels

Intake and Exhaust Upgrades

A GTS produces about 330 hp, while the 2005 Boxster S makes 280 hp. To close that gap, start with a high-flow intake system and a full exhaust. Look for headers, a sport catalytic converter, and a cat-back exhaust from brands like Fabspeed, IPD, or Carnewal. These add 15–25 hp combined. The intake plenum from later 3.4L engines can be retrofitted with adapter kits, but stick with aftermarket for simplicity.

ECU Tuning

A custom ECU tune is essential. Companies like Softronic or AP Racing offer remaps for the 2005 Boxster that raise the rev limiter, adjust fuel maps, and remove torque restrictions. Expect gains of 10–20 hp. Pair this with a cold-air intake for best results.

Cylinder Heads and Cams

For serious power, consider upgrading to 3.4L cylinder heads (from a 2006–2008 Cayman S) and performance camshafts. This requires engine disassembly and professional installation. The 3.2L block can be bored to 3.4L using custom pistons, but that’s a full engine build.

Suspension and Handling: Sharper Like a GTS

Coilovers or Lowering Springs

The GTS rides about 10 mm lower than standard. For a 2005 Boxster, install coilovers with adjustable damping (e.g., Öhlins, KW, Bilstein). Alternatively, lower the car with sport springs (H&R or Eibach) paired with upgraded shocks. This reduces body roll and improves turn-in.

Sway Bars

Upgrade front and rear sway bars to 27 mm (front) and 22 mm (rear) from a Cayman S or aftermarket (Tarett, ECS Tuning). They significantly reduce understeer.

Control Arms and Bushings

The GTS uses stiffer bushings. Replace your worn rubber bushings with polyurethane from Powerflex or Sempor. This tightens chassis response without harshness.

Brake System: Stopping Power

Rotors and Pads

The GTS has larger rotors (330 mm front, 330 mm rear) vs. the 2005 Boxster S (318 mm front, 299 mm rear). You can adapt Cayman S brakes (2006–2008) with carrier brackets and 330 mm rotors. That’s a common upgrade. Use performance pads like Pagid RS29 or Ferodo DS2500.

Caliper Options

The 2005 Boxster S uses 4-piston front calipers. For GTS-style braking, upgrade to 6-piston calipers from a 997 Carrera or Cayman S with custom brackets. This requires 19-inch wheels to clear.

Exterior Styling: GTS Look

Front Bumper and Spoilers

The 2005 Boxster front bumper doesn’t match the GTS’s aggressive lines. Aftermarket replicas of the GTS bumper (with larger air intakes) are available from Duraflex, Vorsteiner, or GT Racing. Fitment requires trimming and painting.

Rear Diffuser and Spoiler

Add a GTS-style rear diffuser (ABS plastic) from AC Schnitzer or aftermarket. The GTS also has a small trunk spoiler; you can buy a replica spoiler lip that glues onto the factory lid.

Side Skirts and Wheels

GTS side skirts are more sculpted. Look for OEM-style side skirts from a 2009+ Boxster (they fit with modification) or aftermarket carbon fiber skirts. For wheels, replicas of the GTS’s 19-inch Turbo wheels (often called “GTS wheels”) are sold by many retailers. Tire sizes: 235/35R19 front and 265/35R19 rear.

Interior Upgrades: Sporty Touch

Steering Wheel and Seats

The GTS gets a thicker, Alcantara-wrapped steering wheel. Install a Sport Design steering wheel from Porsche or a MOMO aftermarket wheel with an adapter. For seats, find used 987.2 Sport Seats with deeper bolsters—they bolt into the 2005 Boxster with minor modifications. Reupholstering with Alcantara and contrast stitching adds the GTS feel.

Gauges and Trim

The GTS has a Sport Chrono package with a stopwatch. You can retrofit a Sport Chrono gauge from a later Boxster (requires wiring and coding). Replace plastic interior trim with brushed aluminum or carbon fiber from aftermarket suppliers like RPM Technik.

Practical Sources for Parts

Avoid generic marketplaces for these specific components. Instead, use specialty retailers:

• Pelican Parts or ECS Tuning for OEM and aftermarket parts.
• Suncoast Porsche Parts for genuine Porsche items (brake brackets, sensors).
• Fabspeed or Carnewal for exhausts and intakes.
• GCG (German Car Group) for used performance upgrades.
• Local Porsche dismantlers for used suspension arms and interior bits.

Always verify part numbers for fitment. The 2005 Boxster (987.1) uses different wiring and connectors than the 2012 GTS (987.2). When adapting newer parts, expect to need brackets, harness extensions, or coding.

Recommended Build Sequence

If you’re building a GTS-style 2005 Boxster, start with the suspension and brakes—they transform the driving experience immediately. Then add exhaust and intake for sound and power. After that, focus on ECU tuning. Finally, tackle exterior and interior cosmetics. This order keeps costs spread out and ensures the car is enjoyable from the start.

Final Recommendation

A 2005 Boxster with GTS parts can match or exceed factory GTS performance for a fraction of the cost. Focus on genuine brake upgrades from a Cayman S, coilovers from a reputable brand, and a careful intake/exhaust combo. Don’t neglect cooling: the 2005 engine runs hotter with more power, so consider an upgraded radiator from CSF or Setrab. For the best value, buy used suspension and brake parts from crashed Caymans or 911s. Always have a professional mechanic inspect any modified parts—especially wiring and structural components. With the right approach, your 2005 Boxster will deliver the thrills Porsche intended for the GTS badge.