"Necessary" is kind of subjective, as paradoxical as that sounds.

I relocated mine to the trunk, and moved the windshield washer resevoir to the battery's former location in order to free up the passenger front corner for a cold air intake box and to improve weight distribution.

I made an aluminum bracket to support the underside of a plastic battery box purchased at WalMart. I mounted it in the passenger side spare tire well. Only the top of the battery box sticks up above the carpet level in the trunk. I used a 2 gauge set of jumper cables (24') and cut the handles off - soldering both cables together into the lug for the hot cable. I grounded the battery to the chassis in the back. I also ran 3 10 gauge ground wires up to the 1) computer, 2) tranny, and 3) engine block. All the ground wires/cable run through a simple battery disconnect switch mounted to the plastic shroud which covers the fuel filler hose inside the trunk. So when I work on the car, or want a simple theft deterent, I 'disconnect' the battery ground inside the trunk.

I ran the hot cable right under the carpet up against the back seat, and used a slug-cutter to pop a 1" hole in the floor of the trunk right above the rear end on the driver's side. The twin cable runs up the driver's side of the driveshaft tunnel by the fuel pump and the rear brake line valve/splitter. It runs up the tunnel, under the brake booster, and through the driver's side strut tower 'tunnel' to a power distribution block I installed on the driver's inner fender - under the radiator resevoir mounted on that side.

If you'd like to see pictures, email me at myount@senndelaney.com and I'll send some along to you. This project was much more time consuming and difficult than I thought it would be. But the results look very professional. The cable is heat shielded with aluminum gutter flashing on most of the underside of the car as the driver's side exhaust pipe runs almost underneath it for 4-5' under the car.