for street, without a doubt SMG. rush hour traffic, ease of driving, ability to pass it over to a newbie driver, etc... things you just complain about or can't do when you have a stick...

for race/track, stick.. i've been able to get smg to goof and had to recover while at speed... same complaint from the instructors at spartanburg as well as racers who have tried the m3 smg car at race events... extremely hard to do in a street environment tho so no real worries if you never reach the limit, but for those that think about a race conversion later on, think twice about smg...

cost to work on aint that crazy. its the SAME tranny as the stick except it has extra parts. the extra parts are the actuator and smg pumps... so its not that much more. the e60m5's tranny is a true sequential and will be absolutely different then any h pattern shifter...