Well let me say that I had the stock 18's tires on Pegs and the ride was comfortable however it wasn't the best for handling.
I then switched the tires to PS2's on the Pegs and I noticed that the ride quality suffered a bit but they were definitely much better tires.
Then I replaced the 8" Pegs with 8.5" Evolve H5's with the PS2's and noticed a big difference in ride quality.
With that being said, I can't imagine that you guys can't see much different between 19's and 18's.
I then switched the tires to PS2's on the Pegs and I noticed that the ride quality suffered a bit but they were definitely much better tires.
Then I replaced the 8" Pegs with 8.5" Evolve H5's with the PS2's and noticed a big difference in ride quality.
With that being said, I can't imagine that you guys can't see much different between 19's and 18's.