I really like the my Shift Kit, nice control bore length, good amount of porting, and reasonable bore selection. I just wish they offered a 16" tip and one size smaller bore diameter.
BL barrels are also a good choice, cant go wrong either way. Where are you finding one for sale?
MacDev Militia: Clone GTi with Shift Kit, GTi Valve, Pooty Bolt, & Violent Series Trigger
dp Fusion FX with TechT HUSH Bolt & TechT LAW RAM
Disruptive Balance Barrel, Sly Pro-Merc Diesel Barrel Kit, dye Rotor with Exalt Speed Feed, & Crossfire SS HPA 68/4500 Tank.