So, I have an xcr-l and I had plans to make it into a dmr. I already got a scope and mock suppressor, and I plan on putting a 509mm 6.03 tightbore in it, as well a a harris bipod on it. I know what I like on the externals, but I don't know a whole lot about internals. It is an all stock echo 1 gearbox, and is shooting about 400 fps with the stock 363mm barrel. I don't want to spend a ton of money on upgrades, just wanting some suggestions.