I was in an SCCA IT race earlier this year at Portland Int'l. A VW Corrado VR6 driven by August Macbeth, a guy on his Novice license, was VERY competitive. Long time hot shoe Ron Tanner, in a 280Z, set an ITS track record of 1:31.157, but August ran tough with a fast lap of 1:32.060.
If you're racing out East, I'd think that VR6 power, combined with GTI brakes, would be competitive at Watkins Glen. Thinking about it (it's been 20 years since I raced in the Northeast), Lime Rock isn't exactly a handling track -- more of a momentum track. I think the VR6 could do well.
While in its day the Corrado VR6 won SSA, the A3 VR6 GTI was never competitive in Showroom stock (unless it rained). I don't know how much IT mods will do to its competitiveness. With all the weight in the front, you are going to need to be creative to get some serious front (neg) camber or you'll eat front tires at an alarming rate. When the VR6 first came out, I got VW NA on the phone, when I saw 295 degree oil temp on a hot day at Gateway Int'l. VW's tech guy told me not to worry about it. So it can really take a beating (or heating).
Good luck -- it's always fun being an underdog -- plus the corner workers love it when you go past their station with your inside rear wheel a foot off the asphalt!