Hey Morrokain, it's not a huge strain on the system in practise, I have a far more complex collision detection/ smart flak fuse system than what you're calling for and it works fine. Honestly you'd only need to write the script once.
Basically you shoot only NO COLLISION class projectiles, every frame you filter out your projectiles.
Do a check against nearby entities using lazylib, make sure it isn't the source ship. If it's any other ship or an asteroid entity, apply damage to the intersection point using lazy lib.
Done, fairly straight forward, you could knock out that script in half an hour or so.
All that said I probably wouldn't recommend it, as everyone else uses the same collision classes, and this keeps the game balanced and fair