Ok the most that amp will put out rms wise is 2000watts (if that, some say their underrated and others say their overrated but were not discussing that at this moment), that amp will be ok with an 18" FI BTL or 2 15" FI BL's. What other equipment will be in this car's install? Whats your budget on what you want to spend for a subwoofer? What is the max space you have to work with, you said you have a trail blazer so space should not be that much of a problem? right now im just wanting to put some bump in my truck, then around Christmas i will have money to get like a 4 channel amp and then new interiors all around with tweeters. im looking to pay no more than 750 for my sub(s), and no space is not a problem.