From what I understand by talking to this Mechanic dude, who personally has performed a lot of these procedures in Sweden, it is a very impotant upgrade to perform. Probably the most important. Most cars have this done, if not before then at the 24000km service when valve clearances are checked and set.
Obviously this has not been performed on my car and he strongly recomended it. My Diablo has 37000km´s on it and he also said that by visually inspecting it he could determine weather it was necesary to do right away or if it could wait for the next major. It all comes down to how the car has been driven and the way I will drive it he says. Anyone out there with experiences, bad or good about this one???