I'm also curious where you came up with the math for that... I mean, it is a good amount of weight, and it is a decent foot or so ahead of the axle line, but equivalent to shifting the 400+ lbs motor 11" further back? You'd be a fool not to do it.
However, I plan on relocating mine to where the rear seat should be. Ideally, you want as much weight as possible BETWEEN the axles. I've driven with ~100 lbs worth of 2x4 carpets (Home Depot was giving away their "sample" rugs, they make great low profile creepers haha) in the hatch area. Made the car understeer much more than normal, then catch traction and transition to a bit of oversteer.
Then did a burnout? Come on man, we all know that is the last step in any Supra repair... where's the footage?
Possible to attach to the bottom of the passenger seat somehow, that way it slides with the seat? Might have to position it in such a way that the trans tunnel doesn't get in the way...
I wish they made a set that would work for the widebody. They look alright, they're light as a cast wheel can be, and they're cheap to boot. However, they don't go any wider than 10" unfortunately.
Quite a while back, I bought a set of OEM Ford Contour fans, that were custom fit to work for the Mk3. I've got a PWR rad, and when I recently test fit things, I found that it should actually fit better than the crap Mishimoto fan setup, and I know that they flow a TON of air, compared to the Mishi's "adequate at best" flow.