Not true at all, have seen one blown before from one of our cars coming off a long stage(Rally) with a bad regulator in the alt, so it pumped 21v into it for about 30 miles.
I just did the Taylor battery relocation kit last week. You definitely have to lower the tank to mount it, because the way it mounts is with threaded rod. You have to drill a couple holes, put a nut on either side of it (one under the car, one in the box) and there's really no way to do it with the tank in there. I still need to finish up my wiring, but it came with 2ga. cable, and seemed like a pretty good kit for the money. I got mine for $99 at a local speed shop.