So I found a thing on making my own here:
http://us.generatorh.com/cgi-bin/md/M10055/s2.pl

Has anyone tried to make their own?
I would really like to save $40 if I can make my own with just a potentiometer and a resistor.

And Ive been asking around and can't get forward answers about this still cuz this site has clarified and yet confused me. Do I need a map sensor enhancer for more gains or can I settle with just an o2 EFIE?