A decatted pipe with VXied's is a nice improvement over a stock bike.
Pulls stronger, cooler, easier reving and less down shifting.

 

i don't know why people question drilling the cat out it works very well and DOES get all of the material out you can look in with a light,run a wire or what ever though the pipe and see there is nothing left in it,do it whatever why you want,but drilling works and gets it clean.done this to 4 bikes.