A couple more comments . . .
First, it does not
feel like 90hp due to the 155 ft/lb of torque. When I was test driving compacts, the TDIs felt every bit as zippy as the other compacts I test drove (Civic, Corolla, Protege, Focus, etc.) if not moreso. If that's not enough for you (and you are willing to jepordize your warranty, not to mention your clutch) you can always chip it and/or get bigger injector nozzles /ubbthreads/images/graemlins/grin.gif
Second, there is a huge warranty exclusion for "intentional or unintentional misfueling". This is true for most automobile warranties. If you get a bad batch of fuel--from whatever source--that is probably between you and your fuel vendor. Your auto dealer or manufacturer may cover you to preserve goodwill, but they usually don't have to under the warranty.
That said, VW says you can run TDIs on RME (rapeseed methyl esther or rapeseed biodiesel) that meets the European Specification E DIN 51606. They do not say you can run TDIs on soy based biodiesel because they have not tested TDIs extensively with that fuel. VW of America and/or VW dealers have told some US TDI owners that using biodiesel will "void their warranty" (of course doing so can only void the warranty for problems caused by the fuel, which are excluded under the misfueling exclusion in any case).
The biodiesel/warranty debate is still smoldering over at Fred's, but that doesn't keep TDI owners from running 20% to 100% soy biodiesel without any problems. I've been running at 5 gallons or more of
WORLD ENERGY biodiesel in each tank for 20,000 of the 30,000 miles on my car. I ran 100% biodiesel for most of last summer.
Finally, I don't think TDIs
require any modifications, but if you enjoy turning a wrench, here are some that are worthwhile.
1. Add a bypass filter to filter out the small stuff your full-flow oil filter misses. Oilguard (
www.oilguard.com) and Amsoil (
www.amsoil.com) are popular with the guys at
www.tdiclub.com. IMO this mod. can benefit any vehicle.
2. If you leave the pavement much (or even if you don't) consider replacing the plastic belly pan with the VW factory metal skid plate. These cars have 4 1/2" of ground clearance and a cast aluminum oil pan /ubbthreads/images/graemlins/frown.gif
3. If you want a sportier ride and/or more ground clearance, replace the original dampers with Bilstein HDs.
For more info. on TDIs see
www.tdiclub.com, particularly the
TDI FAQ