subwoofer wiring

I have 2 12inch Rockford Fosgate HE2 Punchs. They are the 4ohm 400 watts rms, and 800 watts peak in a dual sealed box. I also have the Sony Xplod 1600 watt class d mono amp and I need some input on what would be the best and loudest way to wire the speakers to the amp. I think i have them wired up at 4 ohms and it sounds descent but I keep thinking that these speakers should be pounding harder. Could you please help me out and tell me the best way to wire them up with the best sound?
Thanks,
Horntoad03

is this (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3042448066&category=18797) the amp you have?

if so it puts out 500x1@4ohms and 900x1@2ohms
since you have it hooked up to 2 4ohm speakers there are only 2 ways it can be wired up, 2ohms and 8ohms. If you have it wired in parallel at 2ohms then that's probably too much power for those subs, but as long as they don't blow then you're fine. This is the most powerful way to have them wired

On the other hand they could be wired in series at 8ohms in which case the amp is only putting out around 2-300 watts. Check how the wires are hooked up by comparing them to these 2 charts.

http://www.cs.trinity.edu/~areynol1/Series.JPG
http://www.cs.trinity.edu/~areynol1/Parallel.JPG