Support costs per month, well assuming you are over 25 and a great history I'd hazard a guess at 120/month in insurance, double or tripple that if not, rego very depentant but 50/month ACT, petrol, how far do you drive? how do you drive? a tank can be 80 so how many tanks do you expect? Loans you can go onto most bank sites and caculate for yourself. Please tell me you have money saved up first?
I'd get the 34 with the N1 turbo's, more reliable. But personal prefference.
I'd say always get one locally, get it fully checked out in Australia, I've just heard too many things go wrong with imports. Saying that if you can save $10K on an import, that is a lot of repairs you can afford.