So i recently bought a TM sig 552 for 60 bucks from my cousin. He's had it for a while now (for like 3 or 4years now) not really sure how long. and hes done nothing to the gun and since it is kind of an old gun, what should i upgrade first? my main focuses are longevity, range, and accuracy. I know TM guns do shoot kind of low and i do want it to shoot at about 380-400FPS. i really don't want my gun to shoot more than that. I also have a budget of 350$. please and thank you!