The EP400, 500 and 600 and 800(when it is available) all have DSP, which helps keep them from being over driven/bottoming out and maintain a nice flat response. I think how deep they reach is dependent on the driver and cabinet size more than the DSP.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70