first of all the rockford subs will hit harder and louder than any pioneer on the market. If you go with the 4 8" subs you can use the amp in its bridged mode to get 300 wats per sub. Also if you already have the amp you may have noticed that it is much more powerful that it is rated. Rockford tends to under rate there amps by up to 40%. The subs should be wired like this:
| |____ -(sub 1)+_____-(sub 3)+__
| | | | | |
| -(sub 2)+ -(sub 4)+ |
i guess that this diagram wont come out right.
this will be a 4 ohm load assuming all of the subs are 4 ohm subs
I would really recomend two 10" p3's over the eights. But if you want eights then you should really go with JL eights they will sound better than any rockford sub and will cost about the same.
I recomend these subs: