I've ran my Standard BMax 09 4 times now and have to say its already one of the best 4wd cars I've ever driven!
I was going to try Losi shocks on it but the kit ones seam very good so id stick with them for now, then maybe look at getting the big bore ones further down the line. I don't feel there are any upgrades you must have on top of the kit other than some battery posts & straps if your running lipos.
The car in general seams very strong and the only thing I have broke so far is wishbones in sub zero conditions and they were the old style ones!
Mat