Have you checked out the latest copy of European Car magazine? It was ABSOLUTELY the best read, to date. If you haven't seen it, go get one NOW.
First of all, it has my favorite wish list car of all time, the Porsche 911 Turbo (2001) and boy, did they love it. Second, they do a couple of reviews of the old BMW 2002 tii and 2002 turbo. They also have a comparo test of the VW Golf 1.8t vs the Honda Civic Si (It's a no-brainer who won that contest). The rag also interviews a couple of tuners to find out how they'd modify the VW (and Honda) if they only had $3000 to spend. I'll give you a hint, they didn't splurge on the motor. You should also see some of the radical mods those VW tuners did to their lovely Golf 1.8t's; like stuffing the venerable New Beetle 1.8t under the hood (yes, they are apparently different), or swapping the Golf 1.8t front-end with that of a Jetta (curious picture, but nice).
Now if all that isn't enough to convince you to buy that magazine, then the article about what types of modifications you should do to your turbo (yes, they mention the TDI) will send you to the stores promptly. This article covers guages, airflow, chips, intercoolers, exhaust. What a story.
What a magazine... (I think I'll renew) This magazine has changed my thinking about my Jetta TDI. I was going to chip the car first and worry about the other stuff later. Now, I am going to focus on the handling, airbox, exhaust to increase my power.
------------------