Almost all weapons get more unique upgrades to change playstyle. For quad cylinder they are like green rarity jokers. They don't really change anything how gun performs. What would improve them?
Aiming burst: While ADS , shoot really quick four shot burst with 60% critical bonus.
Homing burst: Every three shot shoot one homing bullet.
Maxed out damage feels like what it's base damage should be, so unique jokers should compensate this gun damage somehow. Quad cylinder have too many cons as a basic gun. Low damage, low rpm and low accuracy. Nothing really shines about this gun. I tried my best to build this gun to feel good, current gun level 98, around 30+ different builds to change style much as possible and it's just okay at best. Unique jokers are like pair of sock in half full laundry basket. Nothing really changes.