Cat Only Exhaust?

[Zilverado]

So I removed my rusted out muffler and tailpipes on the weekend, but have not reinstalled a muffler. I just left the intermediate pipe coming out of the back of the cat. I actually like the sound of the exhaust running through the cat alone - kinda "growly" without being too loud.

However, I know my wife doesn't like it very much, so I will likely install the muffler - - sometime . But, in the meantime, is there any problem with running the vehicle this way - cat only? I assume fuel consumption and performance may be effected by the reduced back pressure, or is this all a bunch of "hot air" :p .... sorry, bad pun.

Any thoughts?