installing amp with stock HU

My friend Mike is getting Two Rockford P3s and wants to put them into a sealed enclosure. The only problem is that he wants to keep the stock HU for now, speakers the same b/c they are BOSE and it comes with an amp to that. my only problem is which Rockford amplifier would work the best for 800RMS and how can you go about putting this in?  Thanks in advance.

What vehicle is this in? List the exact model # of the subs please.

You can either wire them in 4 ohm or 1 ohm.  I think amplifiers capable of running at 1ohm bridged are a bit expensive so you should wire them for 4ohm like this if bridged.

You can also wire them in stereo; one on each channel like this to give you a 2ohm load.

With these configurations you will need an amplifier rated at 800x1 @4 omh bridged RMS or 400x2 @2ohm.  The newest Rockford Fosgate amp which provides this is the P8002.  I have one of these but it's pushing a pair of pentagon sony's.  It sounds too loud for me sometimes but I think I'm going to upgrade to P3 someday soon.  I had last years model and it sounded pretty good as well (801s I think).  You can get these from e-bay provably around $300.  I bought mine from best buy because of their great extended 4-year warranty which is pretty liniant.  If anything goes bad you can return it to them and they will send it to the manufacture and you can get a brand new amp.

I hope this helped.  I'm not too experienced but I generally like to match my subs brands and series with the same type of amp.  I think they were designed with respect to each other and diffrent brands might under rate or over rate their products.

alright thanks a lot, also...I heard that you cant change the headunit that easily to aftermarket and do any rewiring because of bypassing the stock amp

anybody have anything on that before i begin to take a look at the vehicle in two weeks. how to go about that

Changing the stock bose to an aftermarket isn't easy but can be done.  Hooking up an aftermarket amp to a factory hu is rather simple.  Just check to see if the amp has speaker level inputs and hook it up (splice into the speakers' wire).  If not get a LOC and splice into you're speaker wire and hook that up to the LOC and then that up to the amp.

As far as amps:  Kicker KX850.2   and the already mentioned rockford would be my first of choices.

Good luck