Not sure what you mean by "emptying" it. If you mean cutting them out, I did it and it did seem to breathe better and for some reason I still dont understand, completely smoothed out the 4-5K vibe I had. Dont expect much in the way of heat reduction though. When I did mine, nobody was making a catless pipe. A better option these days is to get a complete pipe setup from Walker or Muzzy. If you try to cut them out of the stock pipe, you may be buying a new pipe anyway. Its not fun to TIG weld it shut. The stainless piping is surprisingly thin probably to save weight.