I just recently purchased an 07 Titan KC SE 4x4 with the RF 10 speaker system. The sound is awesome, but the sub loses it's kick when you turn the volume up above about 22. I'm curious if anyone has put in a new amp for the sub itself and where you might put it? Also, I've been thinking about putting in a couple more subs under the rear passenger seats but there are small compartments under these seats. Do these come out or what would you suggest? This is the 2nd vehicle I've purchased in my life and haven't ever upgraded my sound system before, so bear with me being new to this area... Thanks for reading and hopefully I can get some help.