Does anyone know getting a differential for an auto M3 will help. Is it worth it???im thinkin it could be a good mod for an auto. If not, what is a good mod for an auto 98 M3. thanks-

Limited slip diffs are good, but the real benefit when going to a new diff is to get the right final drive ratio. The automatic gear boxes come with a higher gear (higher mph vs. rpm) ratio than the manual. Take a look at getter a lower gear ratio gain more torque at the wheels for better acceleration. Talk to some professionals for the right final drive. I changed my final drive (diff) from a 3.23:1 to a 3.91:1 and it accelerates faster, while it may have lost some top speed, I don't care because I'm not usually going 150 mph.