I used a 3/8" extended drill bit (for metal material) from Home Depot on my '05 DL650. I drilled one hole at a time and started up the bike to listen to the difference. I stopped with two eyes and a nose (holes are connected - looks like Micky Mouse) from the top of the baffle end. It does sound better. I have not heard good performance or mpg results for cutting out the entire end. Your bike needs a certain amount of back pressure. I was surprised at how quikly the bike revved with the stock super quiet exhaust. Try one or two 3/8" holes first and see how you like it, or buy a 1/2" drill bit and drill one hole - that will give it a more mellow tone.