I search some videos of M3 with this diff only.
Thanks

The 3.91 will give you a 7% increase in torque to the ground and will raise your RPM by about 250 I think.

From the info I've gathered from a few other forums, 3.91 is best for SuperCharged cars & the 4.10 is best for N/A cars. To me the 4.10 seems to aggressive - but I couldn be wrong, i've never riding in one.

You may also experience greater fuel consumption...

4.10 will get you better gas milage around town but as GREG said you will most likely consume more fuel especially on highway driving.

I have the 4:10 rear installed on my Dinan supercharged M3 - it is what you are after if you are considering doing a gear change. I drive the car on road circuits - no drag racing here - and the ability to pull harder out of a corner is nothing short of awsome. It is NOT TOO agressive of a set up if you are tracking your car. You will use one higher gear on the street than you would normally use with the stock set up - ie if a certain strech of road was usually taken in 4th, now you would use 5th and so on... On the track it saves you from having to downshift into 2nd on the slow corners - all you need on most road courses is 3rd, 4th and sometimes 5th- ok 6th at Road America. Yeah you will lose out on the fuel economy with this change but if you are considering plunking down a couple of grand on an allready expensive car - well does it really matter?? Buy a Prius if you want fuel economy. Buy the 4:10 if you want to be fast.........

Do you know the true differences between the normal diff and the 4.10 in acceleration? 0-100 kmh and 0-200 kmh?

I don't have any hard numbers for 0-100 times but, I can tell you that the difference is absolutly 100% immeadiatly noticable. The thing accelerates so much harder. It's probably one of the best "bang for your buck" mods. It's so much fun to leave your buddies stock M3 in the dust...heh heh.
One thing that I didn't mention before, I believe that there is a compatability issue with SMG. I do know that Dinan has the software for the 3:91 with SMG. My car is the standard 6 speed - no issues. Oh yeah, your tire budget goes all to hell too.....

Do you know the true differences between the normal diff and the 4.10 in acceleration? 0-100 kmh and 0-200 kmh?


yeah, anyone have numbers on this aswell? id love to find out!

and CHiPZ, nice car, a jet black m3(same year too! haha) here too, rock on!

I have the 4:10 rear installed on my Dinan supercharged M3 - it is what you are after if you are considering doing a gear change. I drive the car on road circuits - no drag racing here - and the ability to pull harder out of a corner is nothing short of awsome. It is NOT TOO agressive of a set up if you are tracking your car. You will use one higher gear on the street than you would normally use with the stock set up - ie if a certain strech of road was usually taken in 4th, now you would use 5th and so on... On the track it saves you from having to downshift into 2nd on the slow corners - all you need on most road courses is 3rd, 4th and sometimes 5th- ok 6th at Road America. Yeah you will lose out on the fuel economy with this change but if you are considering plunking down a couple of grand on an allready expensive car - well does it really matter?? Buy a Prius if you want fuel economy. Buy the 4:10 if you want to be fast.........

spoken like a true genius. i agree this mod is for PERFORMANCE AND PERFORMANCE ONLY!!! there was never a concern for mpg when this swap was thought up. if you want to be quicker then this is what you need to think about doing.