Car Stereo Wiring

I'm finally adding an amp to my stereo setup in my Fiero and need advice on how to hook it all up.

I have an Alpine TDA-7564 head unit and a remote CD changer. The headunit has two 4V preouts, and is rated at 40W x4 power (assuming that's max power, probably around 17W RMS). The preouts are Front/Subwoofer and Rear.

I also have an Alpine MRV-F352 5-channel amplifier. It's 2 or 4 ohm loading, except channel 5 (the sub channel) which is 4 ohm. The RMS power loadings are
50W x 4 into 4 ohms + 150W x 1 into 4 ohms
60W x 4 into 2 ohms + 150W x 1 into 4 ohms

The speakers are Eclipse 4x10's up front, model SE8405, and a pair of Eclipse 3.5" in each headrest, model SE8235, all are 4 ohm resistance. 4x10's are 35W RMS, 100W max. The 3.5's are 20W RMS, 60W max

My subwoofer is a stock replacement sub, in the stock performance sound enclosure. It's 8 ohms at 60W RMS power.

SO I have two questions:

1) Becaue the head unit only has 2 channels, Should I run the sub off the front/sub channel, the rears in parrallel at 2 ohms on the rear channel, and run the two fronts off the head unit? Or run the Sub off the front/sub channel, the fronts off the rear channel, and the headrest speakers off the headunit?

2) Is the 150W RMS too powerful to hook up to the 8 ohm 60W RMS sub? Or, since it's 8 ohms, will that mean it's only get half the power (75W)?

Any other reccomendations on how to hook it up appreciated. Thanks!

Anyone?

run from the rear ones

i would run a rca y splitter from the rear out on the head unit to the four full range channels on the amp. and run the sub off the front/sub out. if you set your gains right you will not overpower the sub. you have two of the 3.5s in each headrest? that will put a 2 ohm load on the amp for those channels, and a 4 ohm load on the other two channels.