New member and potential new owner question and yes I have used the search function.
I have been looking at a 2012 C63 with 100,000 km, car drives well and pulls strong . I have had a PPI done and the tech could not find any issues.
My one concern is the idle in gear is a little rough compared to the butter smooth idle of my E90 M3 perhaps someone who familiar with both cars could tell me how the idle compares as I would like to know if I should investigate further before I purchase the car.

Thanks in advance..

Rough idle as in the car shakes, pedal shakes, you shake? Perfectly normal, just the power of the beast.

If there is further investigating to do you should do it, but this is normal so if thats all you have left...have at 'er.

how rough? my idle is rough when I have an O2 sensor starting to go. I've replaced one 3 times now...

Thanks so much for the quick replies, it is not a rough idle like a miss fire but just not what I am used to and to be fair my M3 is manual so it is either in neutral or the clutch is depressed (no Load) this is the only C63 I have driven so I had no past experience to go on.
Love the instant torque and I think a cat delete , tune and pulley will be in order next spring along with the ROW air boxes .
Once again thanks everyone who replied I just needed to hear from guys who have experience.

wouldnt hurt to check the engine and tranny mount. but others could be right, might just be the sheer power youre not used to.

I don't think there is a lot of difference in the power as the M3 is tuned with cat delete pulleys and intake the real difference seems that the power of the AMG is so much more usable in the real world.
I think when the same mods are applied to the AMG it will be a real beast.

The E9X's do have a butterrrry smooth idle and an epic exhaust note. The S65 outside of Ford's Voodoo and of course the M156, is one of my favorite sounding V8's ever.

In addition to the sheer engine size, it could be engine and or trans mounts getting soft.

Apparently, they're somewhat weak on these cars?

Thanks for the advice , I am having new brakes installed before I take possession and will have the tech check the mounts as well.

I love the E90 M3, and its epic wail, but I live in the city. I would never get into that power band. Got to be able to hit more on ramps.

That is the reason I am moving to the C63 .