>> Others asked, "how did you do it"...    I responded:

<PASTED>
As to mounting, I went to the junk yard and hunted down a battery
tray (metal) with hold-down holes on each side (for the j-bolts).  Think I found mine in a dodge colt or something.. Anyhow, I wanted the holes center on both sides, so looked until I found one in repairable shape... next, I lifted the black floor panel in the trunk (passenger side,) and dismounted the computer there...  I built a bracket, and re-mounted the computer behind the jack (drilled a hole in the bracket behind the jack, and fabricated another "L" bracket to hook to the taillight mounting bolts)  I also had to extend two wires going to the computer module, as the cables would reach fine, but these two wires were short, so I spliced in an extra few inches..
 With that head ache out of the way, I mounted the battery tray directly on the sub-floor using sheet metal screws, and cut an opening through the upper floor pan the side of the tray.. (the battery actually sets "recessed" into the floor by about an inch or two.
 With everything in place, the cable running juice forward was the next major problem.. First off, I put a battery kill switch back there, in case the main cable were to ever rub through (the thought of a glow-wire that diameter scares me....  Secondly, I routed around the kill switch with a 15 amp fuse (which lets my seat belts and stereo work with the switch in the off position... Yet would blow in a flash if I had a direct short somewhere...  I grounded the battery in the rear, and ran the + cable over behind the driver-side rear seat, where I ran it out, and under the car.  I took it up the transmission tunnel (Mounted above the driveshaft,) inside that black plastic wire loom material for extra safety.
 From there, the cable went to where the OEM battery sat, and on to the starter.  Also a leg came off to a junction block for power distribution...

Over all.. kinda a royal pain, that required lots of trips to the hardware store cause you were always stuck finding a way around a problem..  Helps to be good a making brackets out of aluminum and such...
 The cover is a simple particle panel, with carpet cover, so it matches factory.......
Hope I helped a little

Keep it shiny side up
 Vince