[Ricochet]

Sure, certainly there are recommendations, but information on good 'ol wiki can either be old, wrong, or biased. Doesn't mean that it is however, I use wiki myself at times, but there you go.

Modern lipos typically have better controls in place to handle things like charging/discharging problems. That way they don't go nuclear if there's a problem and instead just die. That being said, that's why you should never buy cheap ones or charge them on your carpet.

Many modern lipos also list their discharge rate, though for airsoft guns that is usually not necessary info to have. So assuming you have an adequate motor and gear/spring setup, and you buy the appropriate battery for your setup, then no, you don't need a mosfet.

I run two AEGs (no MOSFET) on lipos successfully. It doesn't matter what device or battery you use, you should have the right amount of output for the right device, wether that's an adapter or a battery.