Battery Relocation Kits

Looking to buy a complete kit for my 68 Cuda . I have a lot of $ into this build and would hate to burn it down by using second class mediocre trash. Anybody here have experiences good or bad with the following? CE Auto Electric or MAD? Also, any suggestions as what and what not to do would be greatly appreciated. Running MSD ignition, Ron Francis custom harness, Vintage Air Gen II and dual electric fans. Engine bay is in need of some free space!
Run full length battery cables, negative and positive.
Do not try to run the negative though the chassis.
Run a full length negative cable from the battery all the way to the engine.