I can build you one using an Emag valve or RT Pro valve that will be just as fast as an Xvalve...if you want to stay on the cheaper side. Email me...firstname.lastname@example.org
I will be the weird one and say that you can go with a classic valve for much cheaper than a RT Pro. It will be heavier than your Axe, but if you want
Get an RT Pro ULE or a Tac One.
Email Tunaman, he will hook you up.