Get the 1.8T
They have just a little bit less power then a VR6 but they are a lot cheaper to make fast since they are already Turbocharged.
A stock 1.8T is good for 390hp on stock internals while your "Fast" VR6 isnt. Take my word for on this one. I have several friends that are into VWs and while the VR6 is a little faster stock with mods the 1.8T will kill one unless you spend a ton of money on the VR6.
I say it again..
Get the 1.8T
