I don't spend a lot of time on vwvortex, mainly because I found audiforums.com and audizine first, and figured I didn't really need a third forum on my car.
Regarding Gonzo, I looked them up after reading your post, and I have to say that their website is pretty darn vague as far as what kind of gains you can expect, plus it only really lists tuning for VW MKIV cars, (specifically under their "tuning" menu, where they list zero details about any of the tuning options, at least as far as I could tell). Yes, the engine in my Audi is *mostly* the same, but there are some differences between the transverse and longitudinal versions, and APR is a well-established name in the market, so absent further information, I'm still more likely to be interested in APR than Gonzo.