By marque

Some guides are about a part; these are about a car. Platform histories, what the tuning market offers each one, and which modifications are worth the money.

• Audi

  Quattro, the RS and S cars, and what the tuning market offers each platform.

  14 guides

• Volkswagen

  Golf, GTI, Beetle and the 1.8T — the platforms with the deepest parts bin.

  7 guides

• Porsche

  The 911 through the 997 and 991, and the modifications worth making to one.

  2 guides