love my SMG M3 the SMG1 was on the E36 and more problem prone! think they have ironed this out on the E46 they are a little jerky from cold though but have read a remap that Evolve offer overcomes this and transforms the car!

really happy with mine! owned it 18 months now! goes well for a standard car and the back end is easy to step out with the traction off! i would say try SMG and Manual to see what suits you as it really is personal choice! after going round Cadwell in a CSL i had to have SMG loved the feeling and launch control is a nice little gimic. certainly a lot of car for the money!!

The gearbox oil is suposed to be "lifetime oil" but i changed mine as persoanly i rather be safe in the mind its clean oil going round the box for what its costs to buy compaired to the oil you put in it!!

Vanos filter is another thing i would change! and snapped rear springs are common. Check the brakes for wear as for the lot it cost me £700 with standard disks performance friction pads and goodridge hoses discs were staff discounted. Brakes are the only let down of the car tbh they are pants standard but improved a lot with the uprated bits and served me proud at the Nurburg back in April. there loads of help and info over on M3Cutters Forum.

Good luck with your search......

Here are some pics of mine