Hey got a dilemma. I recently put some 20x10 rockstars on my stock dmax with a leveling kit with 305/55/20 terra grapplers and they rub like no other. I had to take them back because the tires were rubbing on the metal of my bumper. My question would be if i step down and put the 20x8.5 rockstars on my truck would they be to 'skinny' looking and not have that aggresive look? The back spacing on the 20x10 was -24 and on the 8.5 is +10. Would there be a big difference?

The offset alone is going to make a huge difference. And with a leveling kit you should be able to trim some plastic and not rub at all with the 8.5's.