Gold Stabilizer Bar

Silencer would be good. But balancing it would be hard. It's one of those things that might be overpowered or underpowered. If it were to only dampen sound then it would be best for mid-close range in that it would draw less attention to you compared with your teammates. But at long range the impact and bullet tracer would still be a huge giveaway.

In CSGO the silencers also remove bullet tracers but that would probably be too much.

And plenty of other games weaken your shots when you equip a silencer but you wouldn't want gold loot to have any downgrades.

The problem with the muzzle flash reduction is that equipping any optics will negate the muzzle flash issue anyway. It's only really good if you find the muzzle flash reduction before you happen to find optics. Guns like the Prowler are ridiculous to see with when you're spamming bursts in ironsights.