Yea things like an HO alt, big 3, extra batts, etc.... Don't quote me exactly(a lil drunk and tired right now) but I'm 99% sure they can be wired to 8,4,2,.5ohm final loads.
For 2k I'd suggest u at least have big 3, a nice underhood batt(ex. kinetik 1400 or so), and a big batt out back(Kinetik 2400, XS 3100, NSB90, etc). H/O alt isn't a necessity, but it would put alot of ease on the system as a whole.