I have a 98 A4 and had a forge DV. I hated the maintenance issue, it was a bit of a hassle. I found a simple solution, the TT Diverter Valve works in all 1.8T engines and costs about $45. The TT DV is better than the others. It is the 710-N model # I think. It is the only one they offer for the TT. I have the apr chip and exhuast and it works great and there is no maintenance. I was told about it by some of the apr stage 3 1.8t owners. A lot of them use it and push around 290hp so there were no doubts about my ~210hp 1.8t. Just wanted to share that with everyone.