Saab 9000 – Buy?

This is what I’m talking about:http://tinyurl.com/pe2lck , engine is the B234I, if I see it right. “Vehicle is restless” I would at best tap on uncleanly adjusted stand gas, at worst on finished compensation shafts. What would new compensation shafts cost including installation? What are the weak points where I should look for? Control chains clear, and otherwise? According to the seller, an ignition coil is also over. How much am I going to go there?