lol... well I about to do close to what you are suggesting. I decided to try out the new JL Audio Stealthbox, with a VX1000/Vi amp, an the LoC-22. A little more expensive, but it will be fun.
I actually still have a PAC AmpPro CH41 from my previous system, but I decided I would use the sub leads with the LoC this time around... keep everything in the back. The LoC takes that speaker level input and flattens it out to the amp, similar to what the AmpPro does, but I won't have to pull my radio out and run a cable from front to back, although I'll have to run the amp from the batter to the back... not a big deal.
UPDATE ON THE HK SYSTEM... I was actually able to get the sub sounding pretty good, and it is amazing how much better the overall system sounds with the sub sounding better, and being able to pump some mid-bass back into the door speakers. I treated the rear doors, the majority of the back wall, back corners, part of the back floor, and the sub box with dampening material, but I think what made the most difference was stuffing as much polyfil in the sub box as I could get in there. Even withOUT the seats in the truck I was able to crank the bass EQ slider up to +3 to +4 without boominess. I am finally somewhat impressed with how good it sounded today. It's not going to win any SQ contests, but it might actually be worth the price tag now, although we shouldn't have to do all of this to get it to sound respectable. The more I listened to a variety of music, the more impressed I because with how good it was sounding. The imaging and sound stage is very acceptable. There's not much depth acuity in the front stage, but I wouldn't expect it without some more robust processing. I think I can make it sound even better by treating the front doors, and I may replace the dash speakers with the HAT Legatia L3SE speakers I have... and if they sound good, I'll need to get another one for the center.
At any rate... things are sounding much more positive now.