I bought a genuine one in the end but I did
compair it to the Ford Maverick 2.0 in GSF and its the same. The gates T43003 one is the same as well. I went to my local focus breaker and he had 2 st170's both with snapped cambelt's with just the standard 2.0
zetec tensioner on so that's why I've gone with a genuine one. The tension on the genuine one is a lot stronger than the standard zetec one.