What are you trying to achieve? I mean, what exactly do you want from it? And have you had a search through the forum yet? If not, do it!
 
For the cupra 20vt most would recomend the carbinaro i would guess.

Not tryed it myself due to owning a LCR i hear it gave good figres and a good noise to boot.

To find out more i would recomed you do a search as this subject has been cover many many times.