Catalytic converter vs. Test pipe?

[Glidjetta]

Just wondering if I should bother chopping my 3" test pipe to throw a cat in, I will still need to get a reduction pipe to fit my 2.5" APR exhaust, but the question is will I get the CEL without the cat?
Any help would be great!

[Jetta03]

Re: Catalytic converter vs. Test pipe?

Definitely will get a cel.