Not much of an AV guy, so my terms may be off.

I've heard that if you take neons (a blue neon and red one for example) and wire up the blue neon to the low-pass and the red to the high-pass, you can make the blue neon pulse to the bass line, and the red neon with the highs. Not by means of the music itself, but by the electrical current sent to the woofers/tweeters. Is this true?

I dont know about the high pass... but i know that it works with amps... because i have done it in a buddys car... allthou they blew up soon after.. too much current i suppose...
But a better way would be some sort or relay... to power the neons... activated by the amp.. but i dunno, maybe some one has had better exp with this... they were small neons that we were using... and it was a big amp... rubicon 502..(500rms)

Would the neons mess up because they are pulsing to the music?? I mean...aren't they supposed to have a steady current, not alternating current running to it?? I don't know, just wondering.

The neon in my trunk flashes with the bass. It has a switch on it, to do that or just go on.

u will cook any neon within a short period of time if u wire it to an amp.

That is kinda what I figured Sweet.