I'm a touring guy and want to get an E91 M sport rear wheel drive and swap in a decent power plant.

The options I am mulling over are:

S54 with 6-speed
S65 with DCT
S62 with 6-speed
S55 with DCT
N55 with 6-speed

The S54/S65/S62 would all be stand alone EMS (Emtron), the others would be BMW EMS with flash tunes.

Just looking for the been there done that reasons from anyone that has swapped any of these and wouldn't do it again.

T