Shawn, it's been debated quite a bit on here - there's a lot of information on this including a very recent thread in the drive train section.
That said, there's a lot of different opinions. Personally, I've found that even for just street driving the lsd makes the car both track straighter and reduce torque steer, improving the overall driving experience a lot. That's just been my experience, again, opinions differ.
Well I reckon if you intend to do the odd burnout a LSD is essential, spinning up one wheel looks lame, however peeling off two fat lines behind you as you pass with a cloud of tyre smoke looks awesome. Not that I support hooning on public roads........
I would rather have a 350HP car with a TBD than a 500HP car without. I put a Quaife in my R21 and absolutely transformed the car. It had so much more low speed grip off the corners that it felt like the car had a 100hp less and ran ALL the previously 2nd gear corners in third afterwards.
What's shocking is some very high end sports cars don't come equipped standard with a limited slip. My Lotus didn't have a limited slip.....seriously? $80,000 sports car in 1988 with an open diff? The 016 with porsche LSD is fixing that problem.
Having driven a GT40 (CAV) first with an open diff, and then with an LSD....I wouldn't take one on the road or track without it. Gets the power down more effectively, but the big difference is that torque steer is eliminated making the driving experience more predictable and enjoyable.