I would like to know what are the maximun wheel sizes(front & rear) for ECoupe?
In AMG webpage they got 7-twin spoke with 19'' ET44 235/35(front) and ET44 255/30(rear), as for the biggest sets offered by them.

Someone knows?

I have 20'' with 235/35 ET40 front and rear.

Do you think the E63 AMG Wheels will fit? They are 255/40 18''(front) & 285/35 18''(rear).

Hard to say. Have you lowered your car? I have H&R springs which lowers the car 30mm front and rear. I would say that you should consider going for the stock size of the tyres which are 235/40 front and 255/35 rear if possible.

Brabus lists 275/35 as the biggest wheel at rear and there is notification "Modifications required for sufficent wheel coverage and clearance". There is also 235 width almost in every front tyre despite the size of the rim 17-20''.
On the other hand Carlsson offers 10x19'' with 275/30 so i don't know maybe that rear will fit.

The offset of the W212 E63 front wheels is too aggressive. I mounted them on my coupe, they were a no-go.

Yeah, I got the standard 18'' AMG 235(front) 255(rear). The measures to go for, right?
I did not lowered the car and do not intend to do so.

i have 245/35/20 front and 285/25/20 rear,but i did some rolling in the rear and still have rubbing problems when 2 people in the back.

lucky that you don't have more issues
wrong profiles and your rear tires 285/25R20
are spinning 35 revs per mile slower than your front 245/35R20
cruise control issues abs issues ?
Who fitted them without telling you they were way off?
funny you don't notice braking and cruise control issues
3% difference front to rear is max and you are nearly 5%

285/25R20 rear 235/30R20 front are correct profiles within 1/4% of each other and of stock rolling circumference
Still going to rub in the rears but at least you only need to buy 2 front tires

Are you sure its 245/35-20 and not 245/30-20? Coupe has less room than sedan. 245/35-20 will probably not fit sedan, so how can it fit coupe then?