I know of one case where a guy I know put synthetic oil in his 130,000 mile car (don't remember the type) and was impressed. He said the motor had a slight tick/knock when he first started running it and it went away after about 20,000 miles. He was fully in favor of synthetics, but as we all know, if there are any questionable seals in the engine it will leak.
I run synthetic in my Fatboy and I switched my toy over to it and it started knocking (conn. rod) so I switched back but after reading this I think I'l give it another try
