If your main cat is in good shape, you should be fine with emissions testing, as long as the cat is properly warmed up when the sniffer test is done.
If it doesn't work, you'll be out next to nothing but a few hours of your time VS a huge chunk of change for new precats. You've got practically nothing to lose by trying it.
If you do the gutting, just remember to:
1. Remove your upper O2 in the front, you don't want to damage those. The rear is usually easy to avoid, just mark your digging tool at a point on the shaft where the tip will stop short of the sensor. That way you know just how close you're getting & when to back off.
2. get any debris out of the pipeing before the main cat all the way back to the precats. You don't want to clog up your system.
3.
be careful & take your time, especially when you get near the top of the precat material. You don't want to let any of the material to bounce up into the motor. One CEGer that I've heard of got a little um, enthusiastic, when doing the proceedure & got some of the steel wool into his engine somehow. BAD NEWS.
