I'm just thinking safety since i have not flown with a printed fire wall on any of my builds.
I use 3D printed firewalls in every single one of my builds because Im too lazy to make them out of plywood. They work extremely well! Just get on thingaverse and there are tons of stuff for FT builds. I have only used PLA and haven't had any issues even in some extreme crashes. The power pod can be used as a sacrificial part. Id still leave the pod itself made out of foam and just glue the firewall on. When you nosedive it into the ground the foam pod acts as a crumple zone and absorbs some of the impact rather than the fuselage.
With that being said I am making entire power pods. The photos I attached are of a modified 130% simple cub i just finished. The power pod and the hatch/canopy are both 3D printed. As are the main wheels, servo mounts and control horns. I also added a 3D printed tailwheel mount for the rudder to give me a bit more control on the ground. Not sure how its going to work out.
Anyway 3D printing is amazing for this hobby. I just try to use less infill if I can to save on weight. But those main wheels I found on thingaverse weigh half of what I was originally going to install. Keep in mind if you use PLA you probably dont want to leave the plane in a hot car or it could reach its glass temp and start to get soft. Thats really the only downside to PLA. If you are worried about it use PETG, but i have found with smaller parts I get more rigidity with PLA so i have stuck with it.