14 is safe on any car that is 12v based...most cars actually charge at 14.4 which is WHY alot of amps and CEA rated stuff is spec'd at 14.4... it is the standard... 13.5 is the rarity not 14+...
Oh ya well I am thinking about upgrading my ssystem up to about 1200rms so will have to upgrade the electrical anyways. What would be better 4 12in dc lvl 2s or 2 12in dc lvl 3s?