Should be pretty loud... but you will probably destroy the MOFOs relatively quickly. My friend popped spiders off 4 of them (2 at a time on two occasions) running only 350 watts RMS each (read: he was clipping the living hell out of the amp and running under tuning, though). The coil seems to hold up pretty well but the glue joints leave alot to be desired, unless they have fixed that problem in the last few years.
Also... they are very inefficient, and you could be much louder with a difference speaker. BUT, in short, you will be loud... maybe not competition winning loud, but loud none the less.