I have 17x9 XD revolvers but I am running 285's for my tires. They do throw a lot of debris from the road onto the truck, i haven't gotten any damage from it but it does get the truck dirty.
If you are comparing how much the 16x9 w/ 4.5" BS stick out compared to the 16x7.5 w/ 5.25" BS, then it would be a difference of 2.25".I really like the ATX Artillerys. Those are 16x9, 4.5" BS w/ -12mm offset and a 108mm bore.
The SR5 rim is a 16x7.5 with a 5.25" BS and a +32mm offset if my research is correct. My math says 5.25 - 4.5 = .75" BS difference, add 1" for increased rim width on one side and I get 1.75" extra over a stock rim.