Do it since carwash doesn't like it. That is a good reason!
I am looking right now for 1 mitered 10'' stack for mine. Gonna put the 300 hp. injectors in it and do a drive by on CW at 4 in the morning! That should darken it up even more at night but it will not be as loud as the current setup on th truck which is aimed at the driver being passed by's window.
(don't shoot me when I drive by CW :( )