The purpose of the anti-lag system is to have enough boost on tap so that when you punch the throttle, the motor responds instantly. That doesn't necessarily mean the turbo is at max boost all the time, it's just never off boost. However, there is always a tradeoff between power and longevity. If you want to add one you have to take away a bit of the other. So yes, a force fed engine will live a much shorter life than an unboosted one. But then again, how many such modified engines live out their full potential anyway? Well before the blocks goes, someone will spin a crank or big end bearing, or melt a piston, etc. In any case, cars running such systems are dedicated race machines with multiple back up engines and full crew and shop to tear the car apart after every event and rebuild it with new parts.
