not to say "I" have done this..but, in my state anyway (DE) "I have know buick owners" who have tac welded a round (patrially flattened with holes drilled in same) piece of steel to the test pipe area to look as though the vehicle is running a catalytic converter and go through inspection with this and an emissions chip and fuel pressure turn down to 36 psi. (emission chips available through TT for about $20.00).
I have 42# injectors and just went through inspection with no problems, however dmv inspections differ from state to state. In Delaware they simply roll a small dolly under the car (which has an attached mirror) to visually inspect for the cat.