It depends on what u have done to ur bike .
If ur gonna be dunning id say cpi rocket or sheare .
If ur riding mx or tt ptr mids or ptr highrevs or dmc 916's .
For a good all around pipe u might want pro-curcuit or fmf fatties .
To put it lightly most of the pipes are good but it depends on what ur riding.
There are pipes i didnt mention that are good but if u tell us what kind of riding ur doing we will be able to help u out more