Just my 2 pennies...
It might be worth looking at the A3 3.2 as they are nearly the same car and about 50% cheaper. Same chassis too I think. Then will give you more money for mods as said above turbo charging isn't cheap on these. I had the a3 3.2 and just a simple resonator delete will have it sounding better than the r32.
Only thing to really worry about is the chain. Mine was quiet when I bought it but after about a year I had a grinding noise coming from the chain area. Probably tensioner. I also checked the limits in vcds before so must have happened only after 8k miles of me having it. And as you probably know a chain out job is a good 5k.