i run an offroad x pipe with no cats and i don't have any problems with cel. as long as you install the o2 sensors you will have no problems your H pipe does have threaded ports for the o2 sensors right?
and if the cel light does illuminate its not because the cats were removed it would be because you either have bad sensors or a rich or lean condition pulling codes will tell you what the problem is. the reason i say this is sometimes when you remove the o2 sensors especially if the have some age on them they actually will break or not work properly upon reinstallation so don't panic if you get a cel light just pull codes and go from there and if you have over 70,000 miles on those o2 sensors i would replace them anyways but thats your decision to make usually life expectancy for 1995 mustang o2 sensors are 90,000-100,000 miles..
I was just making sure before installation on monday thanks guys appreciate it. And yes their are spots for the o2 i just was not 100 percent sure that it wouldnt throw the check engine
When I first installed my o/r h pipe (with shorties) my CEL would come on intermittently for about the first month or so, then it stopped. It smelled like it was running really rich at first too, but that too got better. But after the longtube install it didn't do it, I guess the computer was used to it. Just my .02