marwen, *note: HINDI KO PA NABABASA ANG IBANG REPLIES*
Hindi ako audio expert pero based on the equipment you listed, maybe you can use the Alpine 3522S Bridgeable Amplifiers to power one subwoofer each, then use the Tekline TK-8050 to power your MBQuart QM160 TX2 separates.

You will not really miss not having rear speakers. My Pajero doesn't have rear speakers and OK naman siya for me in any seating position (of course, hindi naman audiophile grade ang ears ko).

This way makakatipid ka in terms of space, wiring and equipment. Yung HU, maganda ang mga naririnig ko about JVC and Pioneer HU's. Pero hindi ko kabisado models so wala ako marecommend.

Yung set up nga pala ng ride ko (since pareho naman tayo ng ride) is stock Pioneer HU connected to a Pioneer CDXP1210 12 disc CD changer. Front speakers are Targa TX-420 seps (4") and yung sub is a single Targa X-100 (10") in a sealed MDF box (by GlennSter) approximately .9 cu. ft. (although 1 cu. ft. and ideal para sa sub na ito).

All of this is powered by a single Taiwan Alpine V12. CH1 and CH2 power the seps. CH3 and CH4 are bridged to power the subwoofer.

Benta mo na lang yung hindi magagamit. Sayang lang kung pipilitin mo gamitin tapos pangit naman ang resulta, diba.