Only the 45 series fall within the 3% rule, assuming the former is your OEM tyre size. The 50 series tyre is 4.7% already.
Manufacturers don't recommend more than 3% as it would result in bad FC, incorrect speedo and odo meter reading, stress to the bearing, drive shaft and etc. It could also cause brake failure in high speed stopping, due to insufficient leverage of the rotor against the tire size (it's a different story if you're using dinner plate sized rotors).
Try browsing
www.1010tire.com they have this delightful tyre calculator which includes speedometer and percentage variance for multiple tire sizes.