I purchased a set of sway bars, but had a crazy time trying to remove the 328 one, so I left it in.
E36 M3 rear sway bar for sale. $20 (+ shipping and handling). (with endlinks - <30k mi)
Front sway bar from my 328is (had the M-sport suspension). Comes with bushings. Had 188,743 kms before I changed them. $20 (+ shipping and handling).
Diameters upon request. Or best offer.