its easy to mount them under the dash you can screw them in or use sticky stuff just be careful. in my set up i had them wedged in a certian way between the dash and used some sticky stuff for extra support works but just gotta find the right spot. also yah you definately wanna tap into a 12v source and add switch for it. also another way to go if you do not think it is that great under the dash another easy place to put it is under the seat. in mine i have it above and under and it gives a nice bright effect. you can check out the other neon topic to see my pics or visit the cardomain site.
1994 SSE, 180 t-stat, gucci accented interior, suede headliner, eclipse avx5000 headunit, two 7.8" sunvisor screens, two 7" headrest screens, dvd player / tv tuner, infinity kappa perfect 5.1 components, infinity 12.1 perfect in the trunk, 2 rockford fosgate 350s powers, infinity refrence 7541a, 0 gauge audiobahn high flow wiring, duralast gold battery, sound dampened trunk and doors, xenon-white headlights, 2 15" and 1 20" red neons shine on the back doors, 2 3" and 6 12" blacklights lighting up the whole interior, red leds in the vents, red optx el neon pedals, red streetglow headlight leds, clear corners, pilot seven color angel eyes, blaze seven color underlighting kit, viper 791 xv.