hmm, did they change all the parts on the 18? Or is simply a larger version of the 15. Regardless, with an 18 I'd say 1000 watts would do just fine. Any more and you're putting the driver closer to it's limits with no audible benefit. Remember you have to double power for 3db's. Once you get past the first couple hundred it stops mattering as much, especially for a daily driver, or is this for home?
NVM, just read you sig. So yeah, find a 1000 watt amp and you'll be doing fine. You have a 1200.1 more than enough power!
