Now that I've been researching this for a few days, I've read that the upper reliable limit for the radix is approx. 18K, not gospel of course, but a good rule of thumb.
i.e. if magnacharger new that the radix was spun this high they might not warranty it but its not out of the question by any means.

 

Magna says if you change pulley's it's out of warranty.

 

 

hahahahaha, aint that a bitch

it's a good thing mine came stock with the 2.75 pulley