The "m" designates a mono amp from Fosgate. you must have a "s" series then right?
Anyways, electrical system should be fine when adding another 500/1 just make sure all the wiring is the proper guage and excellent connections are made and you're set.

 

now i know what the "m" stands for. So I guess there would not be any problems putting in another JL amp. That is awesome. Thank you Guys for the response.