In general, the motor is very strong. However, the FRM sleeves are the H22A4's Achilles heel. They do not hold up well to forced induction, especially if you are planning on running anything above 5psi or so. If you are planning on going all out, get it sleeved. It's not that expensive compared to the turbo kit you are going to potentially buy anyway. You won't be disappointed.Originally Posted by Le_Stat