I don't know about gaining a whole lot. I can definitely play it loud longer though. The amps aren't stressed when pushing the subs to the max.
Volume 23 on my headunit was full tilt with my TFE. I set gains on the VP's so that 25 is the max clean volume. Volume 21 with the VP's sounds like full tilt with the TFE. Volume 23 with the VP's is definitely louder. It gets the subs hot on some songs. Anything over 23 for a long time gets the subs hot, so I'm going to say 23 is my full tilt.
For most of the drive, I had my bed cover rolled up and air was going over the amps. The first four hours of the drive were perfect. I was cruising at 2,000 rpm and voltage was steady at 14.6v With that cooling and a great steady voltage, the amps were more than happy. The last hour, it started sprinkling so I rolled the bed cover up. There was also some stop and go driving, so voltage dipped lower, but I stayed in the 14's the whole trip. After that last hour, the amps felt room temperature or a little warmer. Definitely not hot, but warm.
Everyone has talked shit about me having so many batteries, but I don't care because my electrical is solid for these amps. At idle full tilt, 13.7 is the lowest it's ever dipped to so far.
The wardens get smelly before the amps are stressed, so new subs is the next thing I need.
I'm thinking about buying another amp next month before the price increases. Then I'll put the Wardens back up for sale cheaper. I'd like to do four 18's. One on each amp at .5 nominal