I have a 96' BMW 328 IS, do I still need Anti-Sway Bars??

yes you do, i have a 97 4 door and i put the over-sized eibach sway bars in it with bilstein sport shocks/struts and it makes HUGE difference over factory, i can take 90 degree corners about 50mph and its like riding on a cloud at about 120mph, doesnt miss a beat

If your E36 is optioned with sport package, your sway bars are about 10mm thicker than the non-sport already. It's not imperative that you purchase aftermarket sway bars. I think you'd benefit more with a well-tuned coilover setup with stiff springs. I'm running a ground control street coilover setup with 440 ft-lb/550 ft-lb spring rates (front rate/rear rate) and the car as very little body roll. I'd purchase an x-brace afterwards followed by stiffer front sway bars and a strut brace. The stock sport rear sway bar should be sufficient. With a stiffer rear sway bar, you can start to lose grip (think solid axle).