Happen to have a friends son stop by the house to say Hi by chance, who is an installer here in town.
He jumps up in the boat looks at what we have, and dug thru my garage and found a few RCA splitters.
The PPI manual states that you can feed the Front RCA's, then switch it from 4 channel to ST, and it will split the signal inside to all the channels. He took the splitters and split the signal to feed all 4 RCA's. Holy cow. WAAAAAYYY Better! Course it took him only 20 min to go thru the amps and tune in the sub and in-boats for us.... Cost: a few beers. Result: Sweet, given the price point amps.
Just wanted to throw this on here if anyone else was going down this path with the PPI 900.4's...