Then about the same as a clutch change, few extra hours take the heads off and put them back on. Cost could vary pretty significantly depending on where you do it. I'm no murcie expert, but I'm guessing a good 25 hours of labour to remove all the electrical and mechanical connections to the engine, hood, exhaust, mounts, etc, and to get it out and then do the heads.
There are several independent shops that could do this for less than dealer. The Murcielagos usually go to the dealer but the independents are quite used to countach's and diablos. In this case the procedure is no different.
Yes. You are correct !!! I do know the reason. Anti-freeze hose rupture caused sudden drain of anti-freeze leading to sudden increase in engine heat, lower oil pressure, ... Stress on head gasket & rupture of the weakest point !!