As far as a kit for the sub frame connectors:
I don't think it would really be cost effective to offer a kit, shipping would cost a fortune, and they are pretty easy to fab up. Pete's site has some REALLY good info and dimensions and is what I loosely used to make mine.Pete, I hope you don't mind me linking to your site here?!
As for rear ends..Lone hit it on the head. I am going with the R230 out of a Q45 just because:
1. It is stronger than the R200 (which is strong enough anyway) and waYYYYYY stronger than the R180.
2. Has CV joints which are also very strong
3. Most important reason for me is that they are newer, more available, and have LSD (viscous). The R200s with LSD are getting pretty scarse and add on LSD units are VERY expensive.
I am currently working on getting a 'bolt in' kit together for the R230, which will be more expensive than going R200, but I think it will be worth it for the above reasons.
As for headers, I went with the 'el cheapo' Summit blockhuggers, but that is only because I will eventually be building a big ci sbc with TT, so I am saving my header (custom) $$$ for that.
Tim