Barnett 313

What up guys, I wanted to put 4 kicker solo-x 18s in my yukon but now my money is not right. So I was telling one of my so called boys who has 4 MA audio 15s in a explorer , it sounds good too. I told him that I think im going to go with just two 18s and he was like four 15s would be better then two 18s. What do the real bassheads think?