Yes they are extremly open and very free flowing ,and you will need to add fuel in some method , Also a lot of guys who like the TAB look , convert there stock exhaust (vmod) and go to Auto zone and add exhaust tips that resemble TABs for about $8.00 ea ,or they completly remove the 2 mufflers and just use the third volume and add a simular Tip witch looks like the TAB, Just a word running such a open exhaust on the Vrods you will loose a lot of torque on the bottom .