Could be tight getting a car into 15ft.
The lengths are:-
1987–89: 178.6 in (4,536 mm)
1990–93: 178.7 in (4,539 mm)
Which comes to 14ft 10.6 inches.
I've not seen many of these cars around, so not sure on parts availability. However RockAuto stock a lot of parts and fast shipping form the US and a good price even with tax on top. There are a few parts places in the UK, I use to use Bauer Millet if I wanted a part quick, but were pricy, but they have gone now. There is Rusty's Speedshop in Portland, and many other parts places which I'm sure people will add to the thread.
I needed a rear wheel bearing for the Trans-Am, I knew the AC Delco part number, and popped to my local parts place that stock parts for many UK cars, it turns out it the same wheel bearing as a Chrysler Crossfire, so they had it on the shelf.
Personally I think you will be fine for getting hold of parts for that car.