I will be adding a usb hub, usb 3.5 harddrive, and a Liliput Touchscreen to the front of my MCS '06. Where would be the best place to power all these devices behind the dash? I will also need to power a M2-ATX car power supply for my MINI-ITX pc, which will probably be mounted under the passenger seat, there will also be a amp for a sub under the drivers seat. I know the amp will go straight to the battery, but everything else, i do not know where to power them from yet.

Any Ideas would be great!

 

Get your hands on a Littlefuse Add-a-Circuit and tap power
right from your fusebox. I did some searching (I'm in the process
of hard-wiring my iPod and a radar detector) and this looks
like the easiest way to get power and have it protected.

 

Would one circuit be enough to power 4 things? or would i have to get more than one circuit?

 

If you do not mind sharing a single fuse, then you should
be able to wire it for four devices, as long as the total draw
is no more than 10A. I personally got two of them, just to
be on the safe side (they are not too expensive... about $6
and that includes four fuses). The most difficult part for me
was finding out which fuse to piggyback off.

 

Depending upon the power of the amp, you may consider getting a capacitor for it. It will help in the "lights dimming" effect on hard hitting bass. Usuallly it is 1 cap per 1000 watts, but that was back in the '90's.

 

See the thread titled Looking for switched power fuse to tap in this forum for tapping locations.
If you know the power draw for all items you can might get away with one, but as Wonderdrug said, I'd use a couple just for margin of error.