Josh Ricci, the industry's leading (and independent) subwoofer tester posted his test results of the Stereo Integrity 24" subwoofer, which is the subwoofer driver I use in my 24" commercial subwoofers. To say it did well is an understatement. I started this company around this 24" driver because I thought it was the best on the market and Josh's review did nothing but reinforce that thought.
Stereo Integrity HS-24 24" Subwoofer Driver Test
One thing to note is Josh does his testing in the middle of a field to remove the effect a room has on the subwoofer's output. Adding the room interaction would result in even better low-end output due to room reinforcement of the bass waves.
And Josh previously tested the 18" subwoofer driver I use.