A GT 3.2 is mechanically no more expensive to operate than any other V6 Alfa. The suspension is pretty much identical, and the engine, (barring the obvious dimensional differences) is identical. Of the top of my head, the only source of additional expense on a 3.2 compared to a 2.5 is:
- Brakes - bigger at the front
- Outer CVs are unique and expensive
- Oil cooler (if it hasn't been done already)
Er, that's it. Last time I bought a clutch, the 3.2 version was cheaper than the 2.5. Your wheels and tyres may be more expensive, but that is largely under your control. All the work required is identical - changing a cambelt on a 3.2 is the same as a 2.5. You do need to do it every 4 years I suppose rather than every 5.
If we think of the shed-tastic GTA I bought from Dan - about £1500 is going to have that changed from a rather ratty dog to pretty much mechanical perfection. Full suspension overhaul, new brakes, full engine service, interior sorted, new cat back exhaust. So not bad. What is going to be a problem is the body work, which is going to be hugely expensive to get spot on - probably more than three grand. At this stage I don't know how far I want to go in this quest. That's the reason good GTAs are expensive.
GTs are cheaper because it doesn't cost much to get them perfect. Mechanicals - as above. Bodyparts - loads of them around from the cooking versions. So you can get a cheap GT and get it looking really smart from about 6K all in. Doing the same to a GTA - 8,9 K.