FYI, just had the Whiteline 2-piece bushings (KDT917) installed, along with a bunch of other bits (M3 rear upper arms, new rear toe arms, M3 diff bushings, plus front end M3 lower arms and Dinan camber plates).
Performance is improved as you would expect per everyone else's feedback, no regrets.
However, I'm posting this more as fair warning to those of you with northern cars getting up in age... the standard tricks to drop the subframe corner by corner and use sockets etc+heat to press out the old bushings ain't gonna work. Mine is 9 years old now, seen at least 7 Canadian winters, salt, and other abuse. The factory bushings were NOT coming out without a big fight. Wound up going to shop to drop subframe for the install, so I also did stainless brake lines at same time, as well as the diff bushings. In for a penny... There is no way I would have felt comfortable putting the kind of load required using a combination of jacks and jackstands.
Shop said the front bushings came out pretty easily, but rears required putting the subframe on the press - no hand tools were going to get them out no matter how much heat etc was applied. If you have the press, why not use it I guess!
One of the mechanics owns an E90 335i and he's decided when he does this job, he's buying a new subframe... yikes.
Thanks for all who have provided advice in this thread - this is truly a great upgrade that I've been waiting to get to for more than a year. I would only add in that while you're in there, might as well put in an MPerformance LSD at the same time...
Man that slope is slippery.