Interesting! What car do you rally and which events? Me and/or my mate might have got you off the startline somewhere? My mate also owns/crews one of the rescue units you'll see out and about.
It would be good to keep a running total of what you end up spending, I can't imagine there are any S3's out there that haven't had the common faults by now, and either had them fixed or are carrying them.
I purchased what I thought was a very good S3 for a good price earlier this year, but it has still needed circa £800 spending on it (all just parts) to get it to where it should be. I've actually spent more, but some was cosmetic work (alloy refurb etc), and not strictly necessary
Make sure you keep your garage in beers!