I would do a compression and leakdown test before you start throwing parts and money into your car. TheOtherDave is right, your problems don't sound too extreme to warrant a new motor, yet. Are you getting oil all over the spark plug well??? Like on the plug wires too? And for the idle surge, Fast Idle Thermo Valve or the Idle Air control Valve should be looked at. If you have a fast idle thermo valve, I would start there.