Yeah, using two different AMP's no matter if they are exactly the same will sound different. Reason being is that the AMPs will always be struggling for power. So one will get more and another will get a little less. Meaning they wll pulse back and forth. I wouls sell the other and buy one big new rockford. Stick with rockford, they make good AMPs. I do like your 4 10" idea.
can you give me a specific model number and relative price for an amp capable of powering those 4? Alpine 10"s 600w max each i think.
one more question. would it sound bad if they were in two different boxes (2 in each) or should i buy a 4 hole custom box?
Yeah, hooking up two subs in 2 boxes with 2 AMPs would be a good way to run things. Or get one big 4 hole box and have a divider in it so you have 2 seperated from the other two. That would be good only if you want to run 2 AMPs. If you run one AMP go find a 4 channel AMP (rockford fosgate) and make sure its big. Like 200watts RMS times four subs. So i would be looking at a 1000 watt AMP.
pat you just said it wouldnt be a good idea, but now your sayin it "would be a good way to run things." 200 watts rms x 4, a 1000 watt amp? im no nuclear scientist but i think an 800 watt amp just might do the trick.