As the title suggests. On my last car I ran a decat on standard map, and like most modern cars the EML would come on as it sensed a huge rise in emissions. It didn't do much really apart from being a annoyance. After testing the power and AFR with the light on I found that it would run a tad rich on WOT/full boost but still boosted spot on and power was better showing good gains. I know a sports cat doesn't have this hastle but I just don't fancy one. I'm pretty sure the EML would come on as above, however would it still run as my old car did with the light on or would it go into a limp mode? I also eventually ran a 90 degree o2 spacer which stopped the light from coming on as it allowed the lamba sensor to sit out of the flow of gases. Anyone tried this? Thanks.