A4Tech produces really well made mouses.
I been using a Bloody mouse and the sensor, feeling, everything was great and was very cheaper too, like 2 usd to get in a flea market near my house.
I am in the same boat as you. Nostalgia hit me aswell. I have Zowie S2-C for now and from what i remember, clicks on the A4tech AK-47 were so crisp/sharp. Literally for 30minutes i'm searching for inside specs of the mouse, i found only the sensor..