Being 2 years into an 84 turbo restoration with my husband doing all of the work, this will probably cost the same again in parts alone to get into reasonable shape. Assuming the po has neglected it for some time. If your aim is like us to have a car at the end of it all which you know is in first class condition you may want to go down this route. We paid 7k for a car needing an engine rebuild. Which was too much at the time.
Areas to look at -
Fuel system pipes, tanks and carbs, brake lines and master, look for rust on the chassis by the exhaust manifold and on the front cross member on the near side front. Check for damage to the chassis around the engine cage at the rear. You will probably find pin holes in all the ally coolant pipes at the ends, issues with electrics, issues with all mechanical parts, maybe engine rebuild needed, carb rebuild, turbo rebiuld, water pump, manifolds are difficult to get, wastegates corrode, anything plastic trim wise is not easy to find.
Dont get me wrong i love the car and its going to be worth the effort. If you can find a well maintained example you will avoid a lot of pain.