single turbo 3000

A kid at my school bought a 3000 about a year ago, and did some work on it, interior and such, and he told me he was thinking about putting in a single turbo his dad ripped out of a totalled wrx sti. I think his is either a base or SL model, but if he could get that turbo in there, would it be faster than a vr-4, and would a FWD w/turbo have any real advantages?

Well it would be the same idea as a TTing an NA. It all depends how much work he does and how much boost he is (safely) running. FWD has obvious issues with putting power to the ground, however from a roll it has significantly less drivetrain loss than AWD. So there are pros and cons. Single turbos are typically bigger, however the WRX turbo isn't really all that much bigger...alot of guys on 3si are running 2 of them, but typically, when people opt for a single turbo, they go bigger meaning a bit more lag down low, but more power up top. Pretty much this is relatively the same to any kind of forced induction on an NA...you will have the same pros and cons, and everything depends on how much boost you are running.

a single STi turbo wont make him as fast as a VR-4. Its not a big enough turbo to run a single on a V6

No Not at all... First of all a VR4 is able to boost up to 15lbs or 1KpA stock. Now i woulndt even dare boost over 8lbs on a 10:1 engine but thats me...
now for being front wheel drive... well it just wouldnt be as quick as a VR4... If he has a SL then it has stock 220 HP the VR4 are stock at 320-350 range... but if he has a base model then he is set at 160HP (Its Cute :P haha). to be honest he will blow up his engine before he is fast ;). now if he gets it built then thats a dif story.