the us amps are very nice amps but they draw tremendous current they will blow away the optidrive amp if room isnt a problem you could go with a very large enclosure for the 18s and they will drop very low but if you want extreme low with what id assume would be much less box compared to the 18s id do the 15s......for a mix of low and punch the 12s would be the option
in all seriousness if you want ultra low bass with nice spl look at the image dynamics (idmax)12s an fs of 20 hz cant be beat (lol) thye call for small boxes but you give them more box id assume they will drop like nobodys business
I need help on some1s opinion also. I know about subs and amps and all that but don't know too much about watts and RMS. I want a system just like Don says he wants his, to make the car in front or beside me shake. Everything I got in my car is Alpine and I want to stick with the brand, but what I need help deciding on is whether i should buy 2 15" Type Rs and 2 MRD-M1005s or 2 12" Type Xs with 2 MRD-M1005s. If anybody could tell me which would sound better between the 2 it would be alot of help. My problem is tryin 2 figure which is better, not the money
well either way i hope you plan on upgrading your electrical system....the X's will hit hard then the Rs....make your own choices, its your system, there no fun in going with what everyone else wants...