We can have neons here in Indiana aslong as they aren't Blue or Red. I got nailed in Portage, Michigan last year though for my purple neon plate and cobra eyes on the hood of my Sebring. He didn't ticket me, just yelled a bit, tried to scare me, and sent me on my merry little way. Personally I like the Street-glows. I have a purple Street-glow license plate surround on my car now. Don't want to do the underside just yet.
the furthest on exterior mods I would go is maybe stripes if it fit the car and tint, wheels and then I might do clear corners but that is a maybe and maybe lower it if i had a car that would look good lower a little