Relocating the battery to the trunk is not a cheap modification to do properly. You should be using #1/0 cable for BOTH 12V and ground. A dedicated ground should go from the trunk to the engine block, then to the chassis. Some people will tell you that they only grounded the battery to the frame in the back of the car and everything is fine, but that really is not the proper way to do it. Grounds are just as important as hot legs, especially on an EFI vehicle.
A battery relocation is not worth it unless it's something you really really want to do.
Just researched this Mod and came across this thread.
I think a few of you guys may have convinced me to stay away from the Battery Relocation.
One question I do have that may put me back on the coarse for doing this Mod: I am planning to install my sound system in the trunk and will have a couple amps back there that will need power (+).
In the past, I just ran a (0) gauge + back there from up front and a (0) gauge ground to the chassis. Then the usual gold plated fuse block.
Would a rear battery relocation be optimal for this scenario?