Volkswagen Sport Tuning for Street and Competition by Per Schroeder. 

The most up-to-date hands-on book available on buying, tuning and modifying your Volkswagen. This book is an indespensable guide and technical reference for getting the best performance out of your VW for autocrossing, road racing, and street-legal driving.

Whether you have an early "pocket rocket" or a brand-new Jetta, this book weill help you hop up your car for serious sport driving. From the novice to the advanced.