David, it's 7/8" and matches the front heavy duty bar. It 'spec's' the same as the old bar and was designed as such to match the front bar by Addco. Yes, it curves under the diff pumpkin. (did I date myself with that term?)Sounds like a good idea that didn't turn out to be so good.
Is the center part of it straight or does it bend around the diff?
What's the diameter of that bar?
Eric, bounce and rebound are not a function of a properly installed swaybar. (when the car is parked) You should not be able to tell it's there when pushing down on the bumper.I thought a rear bar was not recommended on a first gen and if so a very small one. I did my original suspension about 10 years ago with Hellwig bars and heavy rear leafs. The car was so stiff in the rear you couldn't budge the rear end. I ended up keeping only the front bar then going with Hotchkis front and rear springs because I didn't want to have to cut springs, etc. The front was topped off with GE uppers and delrin bushings. Get this I am still running 14inch wheels but the handling is night and day. The car does not feel any stiffer just different. My back end goes up and down now but the ride is actually smoother. So far I have not seen the need for a rear bar especially on the street.