Don't mean to hijack your topic but I'm in a similar dilema myself, thinking about getting an R34 GTT and wrestling with the pros and cons that come with going to an older car from the 350z. I want something petrol, manual, RWD, similiar power and with rear seats for ~14k.
Audi S5, BMW 335i (dont fancy E46 M3 with 100k miles), Monaro are other considerations. GT86 and TT are out due to rear space.
An R34 Skyline is always something I've wanted to own, GTR's are mental money and the GTT is the only affordable way into ownership. I can afford to be carless from a time perspective when issues crop up but not necessarily from a financial perspective if it turns into a lemon, decisions decisions