I have a Behringer EP4000 I wanted to test the power output on first to see how it relates to the factory specs., and have been too busy to do it yet. I've been having a hard time figuring out if I want the SI HT D2 or D4 versions. I'm leaning towards the D2 as it will give a bit of overhead with the amp. With the D4 it will be a bit shy of the 600W speaker rating. I don't plan to push it beyond this, I just need to decide if it's better to have some headroom so the amp won't clip before it reaches the 600W level. I'll be driving one woofer per channel.