wow, old thread..
I'm parting the car out, as i need to rebuild the tranny soon, 11 psi + auto = fun but not a good idea.
as for the battery, putting it in the trunk is easy, when you extend the +wire make sure it's fused at BOTH ends.
if it some how grounds in the middle while the car is running, you'll save the battery and the alt, not to mention you won't have a fire.
The fuse box in the fender is an ok idea. i'd be concerned about water, it doesn't fit between the fender and the frame. however it'll fit where the filter for a CAI would go, which is really low to the ground, AND you'll still have to extend wires to put it there, so might as well put it inside the cabin.
I had plans to mount it under the rear parcel shelf, so checking any fuses would be no harder than opening the trunk.