I am installing a moderately priced upgrade to the stock system. Adding a new deck, a sub (100w) and some better speakers (4x6 @ 20W, 6x9 @ 50W) with a 200W amp (50wx4)(ALL IN RMS, @ 4Ohms). Can I run the two 4x6 off of the head unit, the two 6x9 through the amp, then bridge the last two channels of the amp for the sub? Any help and advice would be greatly appreciated.