So I'm thinking of getting Forgestar F14 wheels
Front 19"x9" et 20
Rear 19"x10" ex 20

I want to do different sizes on the tires than i've seen on the forum. I live in NY and the pot holes and manhole covers are hazardous. I'm thinking :
Front 255x35x19"
Rear 295x30x19"

Tires - Bridgestone Potenza RE970 AS (stiffer sidewall than the continentals)

I have a 2007 550i with the original sport suspension and I don't plan on lowering it. Will I have a problem with rubbing?

 

you will be okay..
i am running 255/35/20 fronts
and 285/30/20 rears
rolled fenders with kw v2 coils no rubbing even on speed bumps..
good luck... just do it get it and i want to see pics

 

Now I could be wrong, but I think tire height would offer alot more rim protection from pothole damage than width. I was in this same boat with my 19s and went 245/40/19 19x8.5 ET 14 and 275/35/19 19x9 et 14 on my H&R sport and only had very slight rubbing on big dips. I wanted more tire for wheel protection and this combo worked well for me. I think this tire size would be good on your wheel specs as well

 

275/30 F & 295/30 R YES!!!!!!

oh pot holes huh 265/35F R 285/35 !


For cheap insurance run a 5mm spacer upfront with a Et 20 9 inch will be close. Its is close on mine with et 18.