If you can get the XLS 12 or 15's you probably won't need subs. You want impact, moreso than extension. I wouldn't get the 8's though. If you use some rough area geometry (it's not exact science when applied to speakers but still), two 8's is slightly less cone area than a single 12, and about half that of a 15.
You should also check Craiglist/OfferUp for your area. I see a LOT of used CV's for sale on Craigslist at any given time. If they've been taken care of they can be a steal.