This part:
This is the disappointing advice (to me) - especially compared to all the good advice I've gotten from you (Harold) and your shop.
You're seriously suggesting that for a "canyon carver", the "very first modification" would be an LSD?!
And that such an LSD would "SIGNIFICANTLY" (your emphasis) change the handling characteristics of the car?
And this in a thread where the person that asks is still on RFT tires?
First I would contest the "SIGNIFICANTLY" part. Our cars are not simply open differentials, the adaptive braking does more than enough to keep power to the wheels. I would very, very much content that 90% of all people on this forum - including myself - could most likely not tell the difference between a 135i with and without LSD driving on a public road.
And when and how exactly does an LSD "SIGNIFICANTLY" alter handling characteristics of our cars?
A little bit under braking maybe? Mostly on acceleration out of tight corners probably. And how?
Does it get rid of under-steer produced by the awful RFTs?
Does it get rid of under-steer caused by the lack of camber?
Does it get rid of annoying the rear sub-frame flex that is easily more felt than LSD issues?
Does it make the car ride better during "normal" cornering?
How could we possibly know, based on the little feedback we have which problem the OP actually wants to solve?
Your recommendation for an LSD becomes just as good and valid then as my suggestion for an FXX.
If you take a percentage of driving where the LSD makes a difference and combine that with the fact that street driving is rarely possible/legal at the point where the LSD makes a difference, I would very much think that would be the *last* item anybody would recommend.
In fact, it was the last item you (Harold) had suggested to fix my last handling quibbles. Long after tires, camber plates, M3 bits, coil-overs, M3 bushings etc. were recommended and installed.
Again, not my money, what the heck do I care.
Just disappointing advice - coming from what is probably the best, most knowledgeable source of E82 suspension tuning on the market.
Plus I'm just generally grumpy about the rash suspension advice dished out by others on these forums these days, so that didn't help
And to get back on topic, from this follow up post by vampire:
I don't think an LSD would significantly help with any of this.
Good summer tires (PSS, RS-3, Z1, Z2, Rivals etc.) will help SIGNIFICANTLY (lol) with the wheel spin.
Bounciness would have to be diagnosed a bit more, but my first gut instinct would say bushings, shocks & springs could probably cure that. I'd refer to the experts (like HP, TC Kline etc.) who are more experienced with this.
What do you mean by "If it spins, it spins violently"?
Was it bouncing and then snapped around?
You spun on a public road?
DSC off, I assume?