Quote Originally Posted by FieryRobot View Post
Would a supercharger just start to behave badly at altitude, or will you just get less boost?
It should not behave badly. You would just get less boost at higher elevations.


Quote Originally Posted by FieryRobot View Post
I am concerned about passing smog tests later (my truck is new enough to not worry for a while, but it will happen eventually).
The turbo kit will definitely not pass emissions tests. It won't even pass a visual inspection, because the crankcase breather vents to atmosphere. The BOV venting to atmosphere may also be an automatic fail. If you get the turbo, you'd be taking a gamble on the idea that you could modify the kit to recirculate the crankcase breather back into the air filter (through an oil catch can), swap out the lower section of the BOV for the recirculating body and connect it to the air filter, then hope that you can find a performance shop to make a custom tune for you that passes emissions tests. You might even need some custom work done to the exhaust to add a bigger catalytic converter. The high-flow cat in the turbo kit seems pretty small, and is probably bare minimum in functionality.

Prodigy has told me that they have no plans to make their kit pass emissions inspections. If you are seriously interested, call and talk to them about it. Maybe they'll change their mind if they get enough demand for an emissions-compliant kit.