I have a 14 inch set of 2 rally wheels + a set of 2 15 inch rally wheels of same width (different actual widths between 14s and 15s but will sit even with eachother when mounted). I'm planning to put the 14s on the front and the 15s on the back. The tire size is about the same as well. Anybody have huge issues getting something like that inspected in PA?

No issues at all.

Look at the new cars, it's not uncommon at all for a new car to have wheels of 2 different diameters. Look at the Corvettes and the Prowlers.

I thought it was common practice in some new cars to have different sized rims. Thanks for the info.

If you poke around on PA DOTs web site you can find a link to all the inspection laws for the state. I've looked up a bunch of stuff.