got a 2 bros.full system and got the 2 power tips they offer for them one reduces noise by 4to 5 d.other 7to 8 d.i i like the 8 better,dont like the noise on longer trips.i got both tips because of price 25.00 and 30.00.easy to switch out.if your after less noise they both get the job done the 8 is better for me.my advice,get both. lets ride....