the first step is to set a budget, i mean that seriously. FIgure out what you are willing to spend, then buy an amp, for 2 sets of components you are looking at roughly the same price as a decent amp.. then you have to allocate for a sub/subs

budget, amp(s), components, sub(s) that would be my pecking order

and that link is actually www.caraudioforum.com i got it wrong before.. that should also answer the ohms ?'s