I've done it a few weeks ago.
I put the wider ones on the rear, and will do the fronts when the original 225 Pirelli tyres wear out.
235s are the width you get on the R and with Pretoria wheels, no fitment issues, rubbing or any other real difference.
Also because of that I consider them a standard size, not a modification.
I also did this slight width increase on my Corrado back in the day, going from 195 to 205.
I don't think there will be a noticeable difference in grip or handling as the change is very small. Certainly it is far beyond my driving skills or habits to discern.
The reason I did it was for a that little bit more rim protection, it doesn't hurt that I like the look too. ;-)
Check the pictures, but please excuse the dirt!