After reading many posts on Vortex forums etc about supercharged Vr6s, a/f ratio is very important and key to good power. I'm looking to get a Wideband controler to keep my eye on things but am slightly confused. I like the price and look of the AEM one. Does it replace the current exhaust sensor ? Does it also 'control' anything by means of the ecu or is it just a a/f meter ? Cheers Andi