I put a 99 Audi A4 1.8 turbo motor in my 89 VW Vanagon. What you may not realize is the addicting sound of that turbo whistle. I find myself driving that van harder because of it. Because mine replaced a stock 2.1 NA flat 4 the differences were many besides the turbo. I like how yours will be a back to back comparison of the same vehicle with the addition of a turbo. The turbo muffles the exhaust considerably so I opted for a free flowing 2.5" Dynomax glass pack. Vanagons have less area for an exhaust than a Jeep. From turbo to exhaust tip is about 24" including the muffler. It has a deep burble when you have your foot in it, and a whistle when you let off between shifts, but is very quiet in normal driving. If you are going to plumb an intercooler, I used a Saab 900 unit. It is pretty small and they're always available on eBay.