It's already got a baby cam, Hsv headers, tune etc. Definitely noticed a little more responsiveness. Not a really a noticeable difference in power overall though - maybe a few kw. But it already had the mandrel bent y piece that came only on vs s3's. All the earlier ones are the crappy press bent things, so maybe that makes a difference too.
The factory stainless headers aren't great - mine were cracked when I got them and I welded them up. I'm not a massive fan of the ball flange though, and I think they've cracked again where the pipes join. Seems inevitable with such thin steel.
I actually have a set of stainless hm headers for it, but I'll have to modify them to suit my system. See here:
http://www.hmheaders.com.au/shopexd.asp?id=111
Not sure whether they'll fit the vs with variatronic steering AND the vt full circle bellhousing. There's not much room there at all - but their website doesn't mention anything about the variable steering so I may be safe. Doesn't really matter anyway, I'll just change them to suit. And yeah I don't like that crappy kiss pipe. Will eventually get rid of that and do the h pipe like I've done on my Hj.