While I have not driven that particular car on track, I have driven many other exotics (Ferrari 360, Ferrari 430, Porsche 911 GT3 & 911 Turbo, Ford GT, etc.) on track, and have driven the murcielago hard enough on local backroads to form an accurate opinion of how the car behaves. If anything, it understeers a bit for my taste. Come into a corner a little hot, and it understeers and pushes wide.
Get on the gas too hard coming out of a tight corner, and the tail will wag, but because of the AWD system, it's surprisingly tame and easy to control. It's not a hard car to drive, it's really not. My only real complaint with the car is that visibility out the back isn't very good. That, and they are a little finicky in terms of mechanical reliability.
The Gallardo, on the other hand, is built under the new(ish) audi partnership, so it's basically a more exotic version of the R8, and a much better built car than the murci because of this. Despite this, I still like the murci better because it feels more like a lamborghini to me. Anyway, I'm getting off topic now. I hope that answered your question.