glanza's are 133bhp standard and that is fresh from the factory, my engine has done a fair few miles so wear and tear will take its toll plus like i said, im running below stock boost aswell i have a front mount, ct9 tongs hybrid, cracked manifold lol, decat, hks actuator and front mounted air filter. The usual suspects really Yeh maybe mate, a missfire so small that it would be never something i would notice? or like you say a simple tune could iron out the flat spots but im going for a new setup so not to fussed about the result