Your settings appear to be off for your highs. Turn the sub off/bass down, or unplug the RCAs to troubleshoot the highs. Turn the volume about half way up, and play with the settings on the amp until you get the sound you want. Don't mess with the gain, just the frequency settings on the amp. Does your radio have a built in EQ and/or crossover? I'm not familiar with Kenwood HUs. If so, scratch changing the settings on the amp and switch to full mode for the front and rear channels and set everything from the head unit. As far as your subs are concerned, like someone else stated, that box sounds WAY TOO BIG for (2) 10s. You probably won't get the punch you want until you get a smaller box. 10s can hit hard, really hard, if they're in the right box.
P.S. Is this local retailer charging you money just to look at and "tune" your system when they did the initial install???