I've ran a SAFCII for over 2 years both S/C'd and Turbo'd in the same car, stock engine, with now over 110K on it. I'm also not running very much boost either, but I've not had any issues yet.

I am anal about watching the gauges in my since it's a daily driver. I have a wideband and it doesn't go lean EVER, which probably explains why I haven't blown the motor yet. The knock sensor is also not going nuts either, even with only 93 octane being run thru the car. The ECU hasn't been touched, except to hook up the SAFC.

So I don't see how running smaller amounts of boost would be that much different in a 2jz.