If you get an off-road H or X pipe you don't necessarily have to get MIL eliminators if you get a tune to go along with it. A tune can turn off the "check" that the PCM does to see if the O2 sensors are active and working. Also, installing a mid-pipe isn't to to hard if you really want to get an off-road H or X. Sure, they sound better and free up some more HP but if you want to be able to pass emissions, just get one with high flow cats on them.