I'd go with the 4 12s but it shouldn't be that much of a difference.They'll be under-powered but you can fix that later and then it'd be much louder than the 3 L7s.
that sounds good Rob thanks man yeah i just got off the phone with the guy that is selling me the amps and hopefully by the end of today ill be the owner of 3 memphis mcd1000 amps then i just need to get 2 more l7s and i'll be good for a while well still need too upgrade the electrical but yeah