I used Marballizers. Even though they were small for this barrel it still shot them well. Don't go smaller than Marbs though, if anything go bigger.
Flat Black-Good camo and you don't worry so much about scratching it.
Very loud-Good and bad. Scares the hell out of someone if they're not expecting it.
Very loud but that's not necessarily bad, depends on the players preferance.
Spiral porting is hard to clean but if you don't chop you don't have to worry about it. Like to see a chrome one or some other colors also.
I don't know if the spiral porting actually helps or not I just know it looks simple and works great. You'd think with no porting you could shoot out the broken paint but I always rinsed it out, didn't really test that theory. If you can get one for $25 then it's worth it.