IMO, just about any aftermarket s/o labeled as "race only" will garner unwanted attention if you really are "winding it out." Many Euro "race only" pipes, however, such as Akra, Remus, etc., are restricted to 98db as mandated by FIM. This is not obnoxiously loud at "around town" speeds. D&D, Two Bros., and Micron make some of the loudest slip-ons, but Micron does offer an "E" version, sound-restricted for tougher Euro standards.
Bottom line, look for a pipe that is not labeled as "race only" and you should be better off than you are now.