The engine in the z-s is the 1.6 sigma

Will do 150bhp with a 4-2-1, shawspeed ss4 cams and a remap...proven many times and not disputable

Will do around 170 with the above, stronger rod bolts, throttlebodies and omex, possibly more

Youngdan on here runs the mk5 z-s with the same engine, which is also extensively used in kitcars such as caterham/westfield etc. Great little engine.