Can I Mod Using Just The UPC Files?

I've been using TT's tweak utilty to alter the sim and zon files, but I'm wondering if I can just do the same thing with the upc files?

Basically, I'm just trying to increase the speed, hitpoints, and attack damage of my vessels. I'm also trying to increase the amount of shell ammo for all the deck guns. Is this possible or do I need to stick with what I'm doing? Thanks!