Unless my second car with a solid budget I'd shy away from S motors. We bought n63 motor powered 12 and in my opinion the detuned model should have just enough less stress on the parts for longer life span.

Obviously the substantially higher HP and torque will put more stress on the transmission as well so odds are prob more likely to break something in the drive train. But it will be a damn lot of fun until it does.

I want a 50i model after the Tu3 n63. Similar power to the M you are considering but again detuned from the S motor.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)