I am connecting the Stock Bose HU to a Rockford Fosgate P400-4 Amp. It accepts differential balanced inputs via RCA.

Is this what I would use to convert the speaker wire into RCA?

http://cgi.ebay.com/ebaymotors/Rockf...ht_1420wt_1051

 

Yea, that'll make it easy. $15 is overpriced though, MSRP is $7.99.

You can also easily just cut a regular RCA cable in half, strip and twist the wires inside and have one for under $2.

 

two more questions:

1) for that amp, am i better off using 4 ohm or 2 ohm speakers?

2) am i ok using this amp to power the stock bose speakers in rear side panels/deck for rear fill?

 

4 ohm or 2ohm wont really matter in most cases

It can get really detailed down to the fact that some 2 ohm drivers are not as efficient as 4 ohm drivers.
Just depends on what you are looking for.

I purchased some LPG tweets and they are 6ohm and they are some of the best smoothest tweets I have heard. I think they are getting like 40 watts but the are efficient.

I would find a set of speakers you like at a price that fits your budget first. 2 ohm drivers in theory will draw more power from your amp, but not always.

yes you can power the stock speakers as long as the amp will run 2 ohm stereo, which im almost certain it will

 

I have Rockford fosgate p400-4 amp - going to run it at 2 ohms. Birth certificate says 123rms per channel at 2 ohms, and only 74 at 4ohms. Just bought image dynamics cxs62 v2 front components, and getting doors deadened...that's all I will be running for now. At some point I would like to put some kappa 6x9s in Or something similar, just for a poor mans low end. I would delete the rear side speakers all together. Sound plausible?

 

Sounds perfect. Since the speakers are 2ohms (at least I think they are, double check that) and run at 25-125W RMS you can give them 100-123W RMS at the high end of your amp's capability and call it a day. You should be fine just disconnecting the rears, a lot of people do and it shouldnt hurt your sound experience not to have rears for now.

P.S. Based on what I can find your amp supplies 50W x 4 @ 4-Ohms, 100W x 4 @ 2-Ohms, so you'll be giving your speakers 100W RMS max - which should be fine.

 

Thats what they spec, but each amp comes with a birth certificate that details actual capabilities - in this case 123rms