I had a 2006 RRS and still have a 2008 RRS - ran Cooper Zeon LTZ tires on both. I actually found the tire on this forum back in January 2008 when I purchased the 2006 and immediately put the Coopers on it.
I really wish Cooper would make 21" and 22" Zeon LTZ tires. I have not found a tire with an aggressive look in the 21" size. I recently acquired a 2016 RRS and specifically made sure it has 22" wheels. I was going to go with the Atturo Trail Blade X/T or something like that. I have now decided to go with the Continental DWS06.
I still have my 2008 RRS with the Cooper Zeon LTZs, so I am actually going to swap the tires/rims off my 2014 RRS, to my 2008.
I guess I will only have to swap the tire pressure monitors -- I'm assuming my 2014 RRS will not read the tire pressure monitores off the 2008.