Rims for 5 series

I don't know a lot about cars so I'm looking for some help. I wanna buy new rims for my 07 525i and I wanted to buy 19s, but the ones I really like are 20s. I was told 20s may mess with the suspension in the car like it won't ride as smooth and what not so is it better to go with 19s?

19's will ride worse than 18's & 18's worse than 17's. What are you after looks or a smooth ride? 20's fit and some use them, but given the quality of roads in NJ I would caution you to stay 19 or smaller or you will be repairing bent rims often.

Solucky is correct. The bigger the rim, the less tire you have. So, the suspension has to do more work compensating for bumps in the road. It's all about what you want like he said.

I went through two 18" rims (with run flats) in one upstate NY winter. I bought 17's and don't even bother to put the 18's on in the summer anymore.

19's are what i run here is MA.
Just be careful and aware of the roads your driving on. its simple.
if your not paying attention, this is how you bend wheels. Anything more than 19 i think would feel to bulky and big. the 19's already feel large compared to the stock 17's. I cannot complain about the ride on the 19's however.
The only way id do 20" wheels would be on a 550 or a m5. i dont own either of those.
and forget run flats...