I have these fitted to all my Suzuki GT bikes. I found that at idle there is almost no charging so the rectifier was doing nothing..... for good or bad. But when moving the charging voltage of 14.4 volts was present.
So when moving there should (hopefully) be some air flow keeping the thing cool. I have not checked the charging at idle on the 550K3 yet.
Not fitted one to the 550K3. Looks like the original is still working......... but if it fails I know the answer.
Never had one fail on the Suzuki's yet.