Any standalone has its advantages and disadvantages. Removal of the MAF is convienient (no need for stillen for a dual intake) and eliminates a significant restriction over a certain hp level. Where really shines is in its ability to be custom tuned for your setup to a degree the stock ecu can't be. E85 tune is more than possible, and could be activated with a switch I you want. Other features may tip the choice in favor of a standalone (nos control, launch control, intigrated boost control to name a few). The cons would mainly be that you would need a custom tune, on a good dyno, from a tuner who knows his way around the haltech. Source: my very own standalone Z street car. In my case aem, but I have heard amazing things about haltech.
