I'm looking for one 18 i can give 2500w. I wanted one of the new BTL's but I messaged Fi and they told me they were in the process of moving and so production is a little slow right now. Any suggestions on something comparable? I currently have DC Lv.4 12's (love them) running off 2 Kicker SX1250.1's. And my price limit is about 600. Thanks.

Why does it need to be an 18" sub?

There are several companies with very potent 15" subwoofers.

What 15 would you recommend? I don't think I have room for 2 15's thats why I said one 18. I listen to rap and I am looking for super high output at the lowest frequencies. I would use a ported box. Also, maybe I could fit 2 15's if I ran them sealed. Any suggestions on 15's that work well in small sealed enclosures?

RE MT's can do that. I seen alot of sale used to 18". They go for about 400 used

wait wait.. the bl 18 ask for 5-8 ft per sub ported.... the bl 15 only wants 2-5 ported... i run 2 15's ported in a 6 foot AFTER displacement.....what im sayin is... if you have room for 1 btl.. you should have room for two bl's