Rockford vs Sony, which one for subs?

That's a loaded question.  Most people (including myself) here in the forum will tell you that a sony product may not be the way to go (they don't last long).  In my opinion, you'll probably get a better response from the RF amp on the subs.  I would suggest running the 6x9's off of the sony for a week with the RF on the subs and then swicth them and  see which setup sounds better to your ears. 

Duane...

If you think you're confused, imagine how you feel.   

alex75 said it all. Sony is a cheap brand and you get what you pay for: not much. I personally wouldn't let a sony amp power any of my subs. I would deffinetly use the Fosgate for the subs and the sony for the 6x9's. Sony amps also dont put as much clean power as they are rated to. Take that into consideration and dont way underpower your subs. But as said earlier, switch the amp set up and see which you think sounds better. In my opinion. Fosgate is a gaint leap up from sony. Going from Fosgate to sony is like taking a leap of a building, not good. Stick with the fosgate.

Friends don't let friends buy Sony, unless it is all they can afford and their next choice is Bose. However that said, the Sony must not remain in the vehicle for any extended period of time, otherwise a kick right square in the nuts from your best friend is in order to make you snap to. Hard lesson to learn that I do not recommend.

Thanks guys for all of your input.  I think I will try Sweekster's suggestion and try switching after a week or so.  I tend to agree that the Rockford will probably work better for the subs and using the Sony to power the 6x9's will probably extend the longevity of the amp because I won't be turning it up as much.  That's my theory anyway. 

BBusbee