Good day Airplane Guys (not to fear, I fly airplanes also). I recently found that on some of these gas engines, an old sparkplug and non-shielded ignition wire can cause glitches (in FM systems, but probably not in 2.4GHz radios). You may find this link useful:

http://www.rcuniverse.com/forum/m_7471341/tm.htm

Anyway, the reason I am here is to ask if anyone knows of an ignition system that incorporates spark advance? I doubt it's important in airplanes as they run at higher revs all the time, but I'm wondering if advancing the spark might help with my gas car. Possibly not as most advance is used up low in the rpm range, but any thoughts would be much appreciated. Thank-you.

Check out info on CH Ignitions.

Most of the current gas ignitions incorporate auto advance timing. CH, MVVS, RCS, 3w, DA, and RC Xcl are several that come to mind.