I just bought a 2009 ram 1500 hemi with the factory dual exhaust. I had a 2005 tacoma 4.0 with a fowmaster dual exhaust kit and the 50 series muffler. i liked the sound, but the drone in the cab drove me nuts after a while. So i have done some research on here and i think i want the magnaflow 18" and the y-pipe. I see some people have done 2.25 inch outlets and others have done 2.5 inch outlets for the muffler.what is the stock outlet size? What is the reason for people installing the different outlet sizes? My real question is what part number is the 18" muffler and the y-pipe that i will need? I want to order what ever outlet size that will work the best for the muffler shop. I want to make it as easy for them as possible to reduce install price if possible. Thanks for the help!!