I have a 1985 300 TD wagon with 226k on the engine. I understand that diesel cars don't have great acceleration, etc., but I don't think my car is running as well as it should. I do know I have several holes in the exhaust system. Could that lead to lack of performace. Any suggestions would help. Also they sell three different makes of exhaust components, which is the best? Or rather, which make is OEM?