I had 2013 E350 4 Matic which come with tire size 245/40-R18. But I didn't like that low profile type because rim bend easily and one incident hit pot hole which blow out front tire and bend front and rear rim on passenger side it indirectly cause front drive shaft broke where it joint to front differential. about 20k miles after the hidden u-joint in gear inside transfer case is broken. So I change the rim and tire to 17" from 18" using 235/50-R17 same offset 48mm.

This will increase side wall a lot compare to change to standard size of 17" which is 245/R45-17. But know the problem Costco, Walmart and maybe Samsclub will not install the tire because it different than placard in driver door. So I end up installing myself. I am plan to bring to Discount Tire for balancing. I am thinking about doing alignment. Is MB dealer will do alignment if tire size not regular? Can you recommend any shop do alignment for Mercedes?

 

Alignment isn't related to tire profile or wheel size... so while your alignment may need to be corrected with new wheels, the alignment specs will remain the same as original. Unless you have desire to change the alignment specs for a specific reason. You should be able to take it to any reputable shop for alignment.

 

My car had 174k miles now and I never do alignment even I did change all front and rear shock and struts around 110K and replace tire many times. But the car is very stable no vibration even at 95 miles. So I always doubt should I do alignment or not. But I read people suggest do alignment if you change tire.