this is called a air muffler never herd it called this and you are right if you either make the tube bigger or just remove it it will give you a 7.38" of an inch more cfm but its no colder than stock just more flow and as for after market they only give you about 4"to 8" more cfm so if you do a drop in high flow air cleaner like k&n or AMI or one of the others you can save big money and get the same result

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Jay's
09 XL reg cab
L4 2.3 , 40 series flowmaster , tinted windows 5% back 35% sides ,muffler removed from air box mod ,and ac on off switch mod , blinker mod, avs window vent shades
coming soon! k&n drop in/fiberglass bed cover/bed sprayed liner