anybody have an opinion? 18" wheels vs. 20"

It seems there are more selection of E-rated tires in 18" but it's really the overall diameter that matters. I've had both and haven't really noticed any difference. I do think the 20" on my current track look a bit better and are more to scale.

I did screw up on my last truck when I got 305 width tires, although they were E-rated the max psi was only 65 instead of 80.