mmm, i like ;)
it will do its very best to twist the chassis.
mainly where theres the gap between the rails, and also the join from the front rails just behind the firewall, how they overlap the floor pan rails, thats where mine decided to start opening up.
if you seam weld it, and get defected, you will never get the car back on the road. ever.
I'm only caging mine, weld in however, and a serious cage at that, but that should be enough, and I'm after 400 at the tyres, from a turbo motor though, so probably not as much twisting action as you will see.
check out some of the PR guys cars, they stick very very well, not sure how much has been done to them.
its already a 4 link + panhard setup, so not much else to go with for dragging. so stick whatever diff you want under it, 9" are cheap, well known and easy to get parts for.
might ahve to run a taller tyre to keep legal ground clearance though.
keep us up to date :)