It's a tough time to get good prices on GTV/spider as they are reasonably plentiful, and getting to that age, where hi price ones face much competition from cheaper ones like my £400 special.
I reckon in 5-10 years you'll get the kind of prices they deserve, witness suds, they used to be 2 a penny, but now so rare they make good money.
I reckon I have some headroom to spend on my project, but once you start: respray, Cambelt, clutch, rebush suspension, etc. you are heading north of £2k, though it would be very nice then, I'm not sure I'd be able to get a return on investment, so it would have to be for the love of it, not to get your money back, unless you hang on for a while.
Just my view anyway, nice looking phase 1 Spider by the way, must have cost a bomb!
Alfa Romeo GT 1.9JTD