Wheel/tire size and ride Quality?

[Rich84]

My current set up is a flip kit with nitro drop shocks and new leaf springs. Up front I have 3" drop spindles and 1.5" drop coils with stock shocks.
I am running 15' steelies with 255-70-15 BfG's.

My question is with regards to ride quality when changing to say an 18" or 20" aluminum wheel with a lower profile tire. Should I expect to have a poorer ride quality. Our New England roads are not the smoothest. I don't want it to look great but ride like crap.