Is a Helical diff right for my BMW?

[dougisaacs]

Hi all, I'm considering an LSD for my 2006 BMW 330i. It's a road car but may end up doing a few track days in years to come. Looking into LSDs it seems to me that a helical type diff is the type to go for as it doesn't really wear (and it could be in there for quite a few miles) and offers relatively gentle lock up which is good for the road. My understanding is that it won't lock if one wheel is off the ground, and therefore offering no resistance, but otherwise it's an effective system. I'm not clear if it locks on deceleration and therefore causes understeer and I'm interested in anyone's comments on that in particular but any other comments?

[dougisaacs]

Thanks all, FYI mine's the later E90 330i. Apparently Wavetrac do a diff that gets over the issue of an unloaded wheel leading to no drive.
Anyone any experience of these?