First gbb questions
 

So I just bought a Tokyo Maruti g22. I was told that switching the slide for a metal one is the ideal thing to do, but I find no g22 slides anywhere, just g17s and g18c slides, is the g22 compatible with the g17 slide?

In terms of airsoft dimensions, G22 is G17, just different markings on the slide.

Thank you very much, very little is said about the 22 anywhere, so it's been hard to get any answers from anyone

The plastic slide will provide much better gas efficiency. It's never as easy as JUST putting a metal slide on a tm, there's a bunch of other things you need to upgrade as well.

No, keep it stock as long as possible, including the plastic slide.