There's a Russian one on the market. You can ofcourse buy amazing vintage ones with different parts, the reissues have silicon transistors while the 70/80's versions ran op amps, these are better. I think that term Pi came when they made this design
The Pi is just a way of distinguishing that version between the russian one, it doesnt mean that it uses a secret custom mega transistor called Pi. And yes, that is the best 'new' muff around, and for the price youre getting, you should jump around in happiness, get it before its too late.
Well, I got 150 euros around so im gonna buy an original EHX Pulsar and a Russian Big Muff. The original Pulsar is said to have less volume drop than the stereo pulsar. and face it its beautiful