How many times do I have to write this? You can buy carbs that are BASELINED to your setup, altitude, etc., but even a master tuner (which Gary Hoos surely is) cannot TUNE your carburetors for you at a distance; final jetting has to be done on the motor. You can't buy a bolt-on-and-go, pretuned, aftermarket carburetor.
A few bits of advice: 1.) If you don't know how to tune, do your homework BEFORE you buy aftermarket carburetors instead of asking questions that have been asked and answered so many times that we're tied of responding to them. 2.)If you're unwilling to learn, leave aftermarket carburetors the hell alone. 3.) Don't read those component-and-range charts as though they'll tell you all you need to know. In both VM and BS series carburetors, for example, a change in jet needle position will affect the mixture all the way down to closed throttle.
Hoos Racing is a fine, ethical vendor. Another guy who's a master tuner and goes the extra mile in customer support is Michael Morse of 650 Central. I don't know what kind of job Niche does on tech support, but their listing makes it clear there's a difference between BASELINED carburetors and TUNED carburetors, and that's a plus.
One more thing: The VM carburetor design is older than the BS vacuum carbs that are OE on the XS650. Installing VM carbs is by no means an "update."
