My experience is of 2 Gallardos and 1 Murcielago on Dynos. Lambo state Gallardo has 500 bhp. Dyno says 438 and 441 respectively. Lambo say Murci make 580. This car has bespoke titanium free flow exhaust.. Makes 594 bhp.
Add to this the fact that they weigh miles more than the manufacturer states and the Murcielago is made of box girder under its beautitful skin, it is no surprise that the 911 is faster... Ferrari guilty of same, but getting better and now only only 8% optomistic.
Porsche do not tell porkies on the spec sheet.
GT3RS should give 415. Actually give 435. No wonder a 997 GT3RS is as fast as a Gallardo...
They do look good, though. With Audi at the helm, watch the things serve up the proper digits, then they will outdrag all...