Made this one recently.
It is a great distortion. Very open and balanced to my taste. Marshally in sound.
Actually, the only one I find better that the Tempest is the Vortex (which is one of the best drive pedals I have ever built or heard, cannot post a build report for it from some reason).
Aion boards are top notch as always. The best on the market.
Modifications or part substitutions