Radio/tape Cd Player problems of the 2009 Buick Enclave

Purchased 2009 Buick Enclave new in April 2009. Taking it to the dealer for the third time in a week for the steady malfunction indicator light (aka check engine light). First visit (Wednesday) revealed pistons misfiring. Approximate cost - $400. Second visit (Friday) did not reveal anything. Dealer stated that when the mil was 'fixed' on Tuesday, it probably triggered something to make the mil go off for no reason. Or, it could be a real problem that will only be revealed after the mil is reset. If the mil does come back on, it's probably the catalytic converter - which will cost almost $600 for the part and $400 plus for the labor. Mil came back on Friday evening. Third visit is tomorrow and I shudder to think what will happen. After researching online, it appears many Enclave owners have experienced problems with the mil. Very costly problems. Have had the same problems that others have experienced - timing change, batter replaced at an unusually short period of time after purchasing vehicle, power steering, memory seat motor blew, peeling paint from a/c and radio buttons and other buttons, etc. Really enjoyed the Enclave but starting to regret this purchase as it is only 5 years old. Some of these problems should have been recalls and no cost to consumer.