Yes, replacing the stock SA-3 crossfader is straightforward. Simply unscrew the mixer's top face plate (remember to remove the fader knobs and align the phono/line switches straight upward), unscrew the two outermost screws on the crossfader body, pull it out (you may need to sway it left and right for it to budge), then unplug the plug on the bottom. Replace the fader in the opposite manner. Now, if the Pro-X-Fade is compatible with the SA-3, I'm not sure. I've heard that some Stanton mixers need to be physically modified for the Pro-X-Fade to fit but I don't know if that is the case for the SA-3. You can do what I did and try building your own optical crossfader (my old thread is here), but you need to be somewhat proficient with electronics. Mine's still working in my SA-3 and the cut hasn't gotten any duller, nor has it needed to be cleaned. If you do order a Pro-X-Fade and successfully fit it into your SA-3 please let us know. I'd love to try one out in the future.