Thanks guys. Instead of looking online, I actually went to few local rim shops in my area and found the 18" rims with low profile tires. You guys are right. Driving back home on the highway, I felt the roughness a little. It felt weird turning as well (it wasn't smooth, or it's something I have to get used to). So I imagine riding on the 20s with low profiles will be rougher. I even saved $1,500 compared to the 20s I wanted to get
. I'm sure I bought a cheaper brand rims, but it's all good.
Thanks again for your help guys.