i made my own module, looks like it came with the car from factory. my 16V just about is bone stock. only upgrades are: a/c and p/s delete, k&n air filter, and neuspeed spark plug cables. i felt an improvement with the FEM. i have raceland header that im going to put in soon. you can make a FEM that requires a certain rpm and wot to turn on the module.Ok, I've been reading this info, and as my car has a mostly stock 16v (just a header), I'd like to experiment with a simple version of this. From what I read, a stock engine should stay close to an ideal AFR through the higher RPM with the simple potentiometer/relay system connected to WOT and coolant temp sensors, right? I'd like to make the module "transparent" in the lower RPMs though so it doesn't over-enrich and bog down. So how would I make such a thing kick in with extra ECT resistance at a selected rpm value, say 4000 rpms?