One change Lamborghini made in the '06 and later cars was a re-design of the muffler (exhaust) system. The original '03-'05 was a little too tame/quiet for many users. Some upgraded their mufflers to Quicksilver, Larini, Tubi, Kreisseig or other custom mufflers.
There seems to be almost universal agreement that the new Lamborghini designed muffler of the '06 and later Gallardo's are much better than in earlier cars. The sound is much richer and really sounds great at high engine RPM's. I have tried a few mufflers in the past but always wondered if it is possible to upgrade ’05 car to the ’06 muffler. It turns out the answer is yes but you have to do some modifications. This is too long to describe here and is described in detail on the LamboWeb site at:-
http://www.lamboweb.com/Repairs_Sect...06_Muffler.htm
I have not had a chance to put up the audio yet. But I really like the sound. Here is a picture of both mufflers.