hhmm...i have used super tigers for many years and never had a problem with them. i have four st 45's and they all run great. but , they are not as good as they used to be. years ago when they were manufactured in italy they were top of the line. but when great planes became the sole importer for the them they started being manufactured in china and the quality dropped somewhat on them. but i still use them. once the needles are dialed in they run great. when their new out of the box for break-in you must reset the low speed needle. all st's i've owned you have to change the factory set low speed needle setting or they will not idle at all.