Re: Exta Etrigger and barrel
If you are going with a E-trigger to shoot faster, make sure that Halo has eyes.
Not sure if the Xtra has them but, if the Halo doesn't and the Xtra doesn't you will chop some paint. An upgraded bolt would be a good investment. As for the barrel J&J, Dye, and Cp are all fine choices. My personal taste is a Dye boomstick.