Hi all,
I am having quite a bit of issue with my 2011 E550 coupe. Spec: I upgraded the OEM Wheels (F: 235/40/R18, R: 255/35/R18) to aftermarket rims Breyton GTS-AV that has Ps4s on it (F:245/35/19, R:275/30/R19).
The most prominent problem is the noise that comes from my rear, which happens around 2-3000 rpm at around 30-50 mph that shakes the car and vibrates/resonate. ( no vibration when coasting and decelerating) I also encounter a lot more wear in the middle of my Ps4s. I recently just put all 4 new rubber on it, so the balancing should be right. The vibration as of now isn't as signification as I encountered with my worn tires (mostly in the middle), but there is still some vibration now and there. I wanted to ask for suggestions. I am not sure if it is because of the upsizing of my wheels that is causing a problem in the geometry of the suspension? Perhaps the offset, alignment is wrong? Maybe the U joint is worn?
Some other minor issues are Ripped front fender liners on the front side, and rear fender liners falling apart. Anyone tried DIY replacement of the liner before that can give me some suggestion on parts and the process?
Also, since I upsized my tires what Psi would you guys recommend?

I am quite lost here, hoping for some help. Much appreciated!

Sometimes the balance weights can get power washed off at the carwash.
Your wheel bolts may be loose.
You may have a bent wheel.

Have you tried having the tires and wheels Road Force Balanced?

I had mine done at Discount Tire, but they and Americas Tire are both owned by the same company. Give you local one a call and ask if they offer Road Force Balancing.