Is your 91 mechanically sound with respect to being able to receive a turbo? What is the status of the motor? Personally, IMO, no offense, I would not put a turbo that costs $2900 on a car that is probably worth about the same. Just not a good investment. If you can afford a new car, you may want to to take the $2900, sell the 91 and it put towards a factory turbo charged car if turbo is what your aiming for. Quite possibly your 91 has a motor swap and all of this is moot. For that matter Turbo may not be a bad idea...however if not, maybe an engine swap would suit you better than a turbo on an old motor.