Ok.
1. Yes the VR6 has turbo set ups. ATP,EIP,HPA, and the new Kinetics kit for $2200 giving 250whp running 6psi and no FMIC b/c of low psi. Stage II for Kinetics has a FMIC and is supposed to run 300-320whp with a FMIC. Stage II hasn't come out yet.
If you get the 1.8T Know that anything 01 and before is the 150hp 1.8T. The 02's and above 1.8T's (GTI,Jetta) are 180hp. 03 Beetles I believe are 180hp also.
VF Engineering and C2 motorsports have reliable super charger kits for the VR6 cost's around $3000.00-$3500.00 for 225whp however if you do get either S/C kits it would be good to add dsr(dyno spot racing)256 cams which help add about 20-30whp to mid-top range. Dsr's are around $300-$400.
The 1.8T has a lot of potential. I am not sure of apr's turbo kit but there are quite a lot of other turbo upgrade kits for the 1.8T. One modified 1.8T just hit I think 11.32 in the 1/4. I got the info from
www.vwfixx.com
Ok. 1.8T's are easy to make power chips,dp's,diverter valves,exhausts, new mani's, and turbo upgrades.
VR6's if you have enough money to go turbo can be down right Evil. I mean you will be sent into the next dimension with the kind of power. Kinetics is new and the least expensive turbo kit out there but if you want to go a little bit further ATP,HPA, and EIP have some bad ass kits also. 300whp easily seen with these kits.