I've seen a couple post on this site with pictures of neon lighting under the driver/passenger seat and the foot wells for the driver and passenger. does anyone know what size neon bar should be used? thanx

 

I believe a 12" neon will fit under the dash on the drivers side but 9" is more realistic. On the passenger side I believe you can use up to a 15".

Word of caution!!! If you are planning on doing this mod, make sure the neon tubes are not visible to the eye. Have the tubes mounted up inside the dash with a cut-out for the light to shine through.