Just came from the dealer for my oil change ($230 which isn't bad as I've seen some of you pay $300 or better). I have an 08 E90 M3 22,000 miles (completely stock). Dealer told me Im due for spark plugs $579, rear diff $263, and software update $270. He said its the time not the mileage. Diff fluid ok but plugs? Seems a little soon no? Finally the software update. A quick search showed how someone gained 20 hp from the update. You fellas think its worth the $270 or should i just go with a Dinan software update for like $700.