1. differences between RS/RX/ARX/AXIS? They all have the same VQ25DET (in series 1), but Iain is a nerd and can answer the rest of them. Some have HICAS and LSDs, AR-X has more boost and plastic overfenders.
2. The front bar you're talking about is the Aero kit, which was a factory option on RS and RX. I don't think the wing was a factory option, and you'd have to chase it down through Yahoo Auctions Japan.
3. Turbo, but Aaron and Scotty have found if you bore out the banjo bolt on the turbo oil feed from 1mm to 3mm they don't expire.
4. Depending on what car you go for, HICAS might not even be an option. My RS doesn't have HICAS.
5. Yes it is, in Adelaide you need to talk to Brad (ducati02 on here).
6. Series 1 is VQ25DET, Series 2 is VQ35DE. Series 2 also has tweaked bumpers and a tweaked (and probably slightly nicer) interior.
I see you're in Adelaide, you're welcome to check out my RS. I love it, greatest car I've owned, and has the Aero option you're after.
Otherwise come out to the next cruise and have a look. There are a few different ones, I know we're expecting a couple of RSs, an AXIS and maybe an RX, but I'm not sure if there are any AR-Xs in Adelaide.