i just wanted to know what the difference in the two are once installed in a locost, what difference do they actually make, and would it be worth trying to convert my non lsd to lsd? help would be much appreciated.
joel

It really depends on what you are using the car for. If it's for Track use, then yes an LSD makes a difference, but the downside is it does make it a bit more of a handful to drive normally (The LSD makes it understeer a little more). If it's a road car, then I wouldn't bother.

I have a sierra LSD and have had no problems with understeer.

The theory is that if one of the rear wheels spins then the viscous coupling activates. This limits the slip of the rear axle, giving you drive. The effect of limiting the slip will promote a bit of understeer, after the rear end slip has started. I haven't noticed a problem.

An LSD with lobro shafts is about 10kg heavier than an open diff. The weight saving may be of more use than the slip limiting.