[bgyglfr]

My equation for a car like this (without the friend factor) is simple. Figure the value of the car finished. Get a clear idea of what it will cost you to get it finished given your skill set. Estimate what your time is worth for doing the work or dealing with getting it done. Subtract those amounts from finished value = purchase price. Keep in mind that your time should equate to sweat equity so you should come out ahead when it's all done. If not, you need to find another car.