Haha yeah I know, this is SAU after all, why are we talking about BMW's of all things!?
I hear you on the 'don't have to worry about it' side of things. Having been fortunate enough to be have been able to buy a brand new motorbike or two...never really enjoyed them as much as I'd have liked as you worry so much about where you park it, will it get scratched, stolen, attempted theft, knocked over, etc...and yes dirty.
Older less valuable bikes you can just go where you want and park it wherever and not really worry that much in comparison. And who cares if it gets dirty!
Never owned a V8, and have had my eyes on VE / VF commodores for years but with their prices climbing so high, the M3 has come into focus more as prices are much closer than I've ever seen...is it a potential contender now?...of course need to factor in the S65 'maintenance' especially and like you said general M car 'tax'. One can dream anyway.
But more on the reality front - did read the whole 330i thread as well and was a great read too, both threads enlightening as I've never even driven one of these cars! I do recall 330i didn't seem to have the same amount of issues for almost the same car (turbos and related differences notwithstanding)...perhaps down to getting it earlier in it's life so looked after better than the 335i? Perhaps so as your 130i has been good and quite similar, so finding a car that's been looked after well is the especially-crucial-BMW-first-step.