I'm got an SMG in my '02 M3 and LOVE IT. If I had to replace my car with another E46 M3.. it'd be SMG again. The "haters" on here don't like it because they don't know how to drive an SMG. Test driving one for a few KM's does not do it justice. Even in Auto mode, the thing is brilliant. THE SECRET??? all in your right foot. You can leave the speed-shift button all the way to the fastest and still make the tranny granny-shift if you lift slightly with your right foot just as it shifts. It's all timing and finesse. Once you get good, you can drive around rush-hour in the fastest shift mode balancing a glass of water on the dashboard without spilling.
Maintenance costs? Well, of course there's that pump ($2000 new @GetBMWParts) that I already replaced, and the odd relay but that's pretty much it. The clutch kit is the same as a regular 6-spd. In fact, if you're not the best driver and have bad habits riding the clutch on inclined red-lights, you'll probably wear out the clutch on a 6-spd faster than if you had an SMG. Either way, it's a fraction of the cost of repairing a newer DSG gearbox. If/when I move to an E92 M3... that will have 3 pedals thank you. There's good reasons why many top-manufacturers (Lambo/Koenigsegg/Pagani etc) still use single-clutch semi-auto boxes.
My YouTube video
-- RANDY SPARRE --