It shouldn't be a big deal to buy a used ITR. Most owners enjoy and take very good care of their cars ... of course there are always exceptions. When buying any used car:

1) talk to and build a relationship with the current owner.
2) do your background research on the car in general. get a carfax report if possible.
3) get some references from the owner and talk to them to get their input on the car.
4) inspect the car from top to bottom. bring it to a qualified mechanic if you're not sure what to look for.
5) take the car on a couple of test drives. note how it starts, idles, accelerates, stops, shifts, etc.
6) check all fluid levels and maintenance records.

Just make sure you know what you're buying and what the market value is for the car you're looking at. Bring a friend with you so you can get a second opinion. I'm sure some other people may have advice. Good luck.