h-pipe x-pipe ?

okay... i am new to the modular scene. i have had about 8 or 9 fox bodys with nitrous or superchargers, so i am not new to mustangs. from doing searches, i have figured out that if you install an off road pipe you have to do the mil trick or get your ecu programmed? if you install a high flow cat pipe you are okay???? :shrug: i am familiar with just installing an off road h-pipe and every thing is fine. i know this was before obd-2 computers.
 
Sometimes a high flow cat will work, but I've still heard of people having problems with the check engine light. But in general, yes, you need MILs or a chip.