[The HACK]

This is the problem I have with you E9x guys.

NONE of this stuff you guys are arguing matters if the OP isn't even capable of extracting more than 60% of what the car is capable of. You guys focus WAY too much on the equipment, when the REAL equipment y'all need to focus on is the hardware between the seat and the steering wheel.

2 pages of arguing about e-Diff? Really, a good driver learn to extract performance out of the limitations of the car. Traction control and DSC holding you back? Unless you're time-trialing or wheel-to-wheel racing, what you (OP) should be concentrating on is figuring out IF the DSC is kicking in all the time, why it's kicking in. Is it kicking in to save you from the wall @ Auto Club Speedway at 130mph, or is it kicking in because you've extracted all the performance beyond the parameters set by BMW?

And if your answer is "I don't know?" Leave it on. And even if your answer is "I've extracted all the performance I can as limited by BMW's DSC programming?" Leave it on and drive and see if you can pick up another 1/2 second per lap with it on. Trust me. You can.

Before I was made an instructor more than a decade ago, I was SURE I was extracting all I could from my car and the first gen DSC on the E46 was holding me back. I had an instructor with me in one of the B group runs, I kept pestering him about turning off my DSC. He says he trusts my skills enough, he'll allow me to turn off DSC on one condition. That I get a ride with him in his E46 after a session with the DSC off. Keep in mind this is all before Harry's Lap Timer, and all I had was a first gen GoPro HD. So I recorded my session without DSC with the GoPro, then hopped into his car (same model E46 as mine) with the same GoPro. He insist that for 2 laps that I keep an eye on his dash, then he proceeds to drive 5 hot laps with DSC ON.

So all this time, I figure he just wanted to get a few hot laps in (BMW CCA at the time discourage instructors from driving without a passenger, so the only way instructors get to drive is to take a student or fellow instructor out) Once his warm-up lap was over I noticed that his DSC wasn't kicking in, despite the fact that it was on (light off on dash). In 5 laps it maybe kicked in once at one of the slowest corner of the track. When we came back into the pits, he drops me off with a big grin and told me to review and watch my video.

This being the first gen GoPro HD, I couldn't review anything unless I had a computer to download the footage from the SD card. So I got home after the weekend, and watched and reviewed my own driving vs. the laps I caught in the instructor's car. To my chagrin, the instructor's lap time with DSC on was nearly 2.5 seconds faster than mine with DSC off on a 2 minute and change lap. Granted, it wasn't the same exact car, nor the same equipment on the car (his was far more "stock" than mine at the time), nor likely the same tires (I didn't check, my ego tells me that he was on better tires, but in all reality, given how much noise it was making, it's unlikely it was THAT much better than the Extreme Summer Bridgestone S-03s I had at the time).

Don't get me wrong. I wasn't a slouch by any stretch of imagination. It was a track that I had driven at least a dozen days. I probably have had about 30 track days at that time, and was one of the faster drivers in the "B" group. Yet with DSC "holding him back" he was easily 2.5 seconds faster than I was with DSC off.

So why am I telling you all this?

Even if you FEEL that DSC is holding you back, there are always ways you can use it as a tool to "learn" more. And yes, ultimately you WILL have to turn all the driver's aid you can turn off off to become a better driver. But there's NO point where you absolutely can't learn from having some aid turned on to see when and where it's interfering, and to figure out WHY it's interfering to make you a better driver.

If you're still reading, here's my standard disclaimer. You're a freaking glutton for punishment. I would PERSONALLY never read more than 2 sentences I have to write (or say). But if you want to skip all that, here's what you should do as a progression for learning how and when to turn off your driver's aid.

Leave it on. Start taking skid pad, car control, and autocross lessons. Leave it on for the track, turn it off for skid pad/car control/ax where if you do f**k up, and you WILL, nothing bad happens except for a bruised ego and a huge headache fro the rush of adrenaline (ask me how I know). Keep it on for track until you've done enough skid pad/car control/AX to a point where you're absolute confident with your car control skills, knowing you can and will catch mistakes before driver's aid intervene. At this point you should have done at least a dozen track days. Maybe more. You know how to push it and you can FEEL when the car intervenes, and even predict when the car WILL intervene.

At this point, turn off driver's aid, dial your speed back 2 notches, then ease yourself up to speed over several sessions. On an average 4 session track day, I would recommend leaving driver's aid on for the first session while you and the car get used to the surroundings, turn it off for the next 3 sessions, drive 2 notches slower in session 2, 1 notch slower in session 3, then up to speed in the first half of session 4 until you're comfortable driving with DSC off all the time.

Then turn DSC back on and see if you can match your lap time with DSC on and off. IF you can still drive faster with DSC off than on, continue to turn DSC on for a session or two to see if you can get the two speeds to normalize. When you can drive with DSC on as fast as you can drive with it OFF, what you'll find is the next session you turn DSC off, your lap time will likely IMPROVE.

Even at this stage, I occasionally will drive with DSC on for a session or two to assess, just to see if I'm actually better than the car's computer.

All bets are off in inclimate weather though. I once caught a car going sideways hydroplaning @ 90 mph. Let's just say it left a little more than a brown streak in my underpants.