[Dave at Pelican Parts]

Racer Chris from Tangerine Racing has had some pretty good success with strengthening the trailing arm internally--with a bulkhead across (or partway across?) the interior of the arm. I also know people who gusset the main part of the arm to the pivot tube, which would seem to me to be one of the places that would flex the most.

I don't think the reinforcements are worthless, but I think the above would be preferable to the conventional "boxing" of the arms.

And on a street car, I don't think it's needed until you've gotten to a pretty wild car. I've done the curb thing before, and I definitely prefer to live with a little more flex in the trailing arms than to run the risk of killing the tub.

--DD