boombox from car components

I want to build a portable FM/CD system to take to work with me.I want some decent power,and I insist on bass and treble controls.I have a 100 watt Yamaha car amp,some small KLH bookshelf speakers(probably 8 ohm) and good mechanical skills along with adequate beginner electronic ability-and a friend who's an electronics engineer.I'm thinking of buying a decent car head unit (CD/radio,pre-amps out),and mounting it in a tool box or something.The sticking point seems to be the power supply.I want to run off house current-115 Volts-and include a 12 volt option to hang it out of the truck occasionally.How big a power supply do I need to drive this amp and 4 in. speakers? I'm 56,so I'm not going to be playing it at high volume most of the time,although there are moments...Am I crazy to try and do this,or are there reasonably priced components that will work?Thanks for any advice you can give me.
Am I in the right place?

Subwo1-thanks for the reply.I don't know whether my post was too lowbrow,or if I should be in the everything else forum.I don't really want a boombox-that's why I'm building(or assembling) my own.I bought a Sony head unit,22w.x4 channels.I'm going with a 12v.switching supply.I don't know how many amps it should be rated at.If the player puts out 88w.RMS do I need need a power supply capable of matching that,i.e.8 amps,or can I use a less powerful,and weighty,6amp?I also don't know if I can safely run 4 channels into 2 speakers-there's a lot more I don't know about electronics than I do.Thanks again
John, maybe it is just that my analog experience extends quite a bit out of the audio field. Yet, there will always be more that I don't know than I acttually know.

We need to consider that the stereo draws current just to run at no output, say, 1/2amp. We also have to consider that the 88watt output is the rms rating for 4 channels, but the switching power supply has to be able to be rated for at least the peak or maximum draw. Yet, since you will only have two speakers hooked up, you can benefit by using a power supply rated for just twice the rms rating, or 100w peak. Smaller sizes are cheaper to make, smaller, and more available.
You can run with only two speakers, that actually helps you to get away with a smaller power supply. Use only the front two or the rear two, and tape up unused wires. One thing to remember is that some switching power supplies can be finnicky turniing on under a light load. But hopefully you can overcome that problem by making sure the power amp is turned on when you power up the supply. Also allow the equipment to be able to get air for cooling.
stereo to go

I'm planning to fit my parts inside a large plastic tool box.The power supply I'm considering has a fan;I'll also put holes in the bottom and maybe louvers on the sides of the box. I'm a carpenter,and I make lots of dust on the job,so I want to get ventilation without introducing dirt.I may put the CD player on a slide mount,with a flap to cover it when it's inside the box.At this time I'm not planning to use the 100w. amp-I have enough uncertainties as is.