J&J kits,Custom Products 1-piece barrels, Original Warped Kits (Custom Products made these kits for Warped).
AKA Sidewinder Reg.
A+ "No Rise" Feed neck
Egg-volution with Z-board
Custom Products Barrel Kit and Drop
Almost anything will work.
Well made, Good anodizing, variable bore sizes and lengths, case.
Depending where you get it... price.
The folks at custom products make good barrels. Every barrel I have ever used, that they have made, has been well crafted. The hard anodizing on the aluminum piece is excellent. I have yet to see a CP barrel with a bad anodizing job. Overall... these barrels are well made.
Variable bore sizes. The 'backs' of this kit come it .682, .685, .689, .693 and .696. The difference in bore size is just enough to make a difference (meaning you don't get useless bore sizes like .688 and .690, which are too close to do much good because the paint itself can range .002 inches in diameter at the seam.) The overall barrel lengh can be 10, 12, 14 or 16 inches. Length of barrel is purely preference, I like the 14 or 16 inch myself, but if you are a varity man you will like this kit. Over all, if you can't find a back to shoot your paint with this kit... you paint is bad or wasn't formed right.
Case. You get a nice soft case to hold all your backs and fronts in! Keeps things safe and organized.
Price. I got a deal from the manufacturer (I meet the guy, he cut me a deal). But if you get them from some places you might be turned off when you see a $250 or $300 price tag. Don't worry... shop around. There are other places that sell these kits economically. And even if you do pay a little more for these... it will be worth it. They are quality.
Buy this kit: it will vastly improve your accuracy and overall game.