i'm a little confused because i'm looking to put new tires on my 15'' wheels on my car....the stock size tire on the wheel is a 185/65/15....

thing is, every 15'' wheel i've ever had, i've put 195/50's or 205/50's on them....is it going to bother anything if i decrease the sidewall down to 50 or widen the tire to 195 or 205?