I want to do a duel muffler project on my xB but not sure of what tool to use to cut out other hole, I want to make it neat and look good , not like crap, Thanks for any pics and any Ideas what to use,

 

I put on a dual tip in the stock location. I used a dremel to do the mail cutting. Then I used a sanding flap wheel that mounts to a cordless drill. I really helped round out the corners smooth. Then I just used some sand paper and did one final pass on it. After I got the tip installed it wasn't completely straight. So I went back in with a file, inbetween the tip and the body and took a little more off to even it out. I'm just really picky like that.