I have a '99 WR400 and have the FMF Q and the Pro Circuit R4 for it. The R4 is basically a straight pipe and is louder than hell with the Q being somewhat respectable. There is a slight power difference in the two with the R4 feeling like it accelerates just a tad bit faster.
If this is a street application then the Q is the way to go since the popo is going to hassle you if you are too loud. Plus on the street I don't think you would notice the power difference anyway. Since mine is for the track only I run the R4 and use the Q if I am going off roading somewhere where they check for noise.
Hope this helps.
If this is a street application then the Q is the way to go since the popo is going to hassle you if you are too loud. Plus on the street I don't think you would notice the power difference anyway. Since mine is for the track only I run the R4 and use the Q if I am going off roading somewhere where they check for noise.
Hope this helps.
