PDC

Will this slightly taller diameter front and rear throw anything off?

Factory spec for 06 SL65 is 255/35/19 front and 285/30/19 rear. That provides 26" diameter front and 25.8" diameter rear.

The slightly taller tires would be 26.7" front and rear. So the front to back balance is dead on, but .7" more height. Well within rim width.

Sound O.K.?

threeMBs

Yes, you'll be fine.

Same diameter as many use on 20": 245/35-20 & 275/30-20.

PDC

Great! Just ordered a set of Conti Extreme Contact DWS in those sizes after reading your post. Thank you.