Best pipe for price I got choice between and would like your opinion. Powercore 4 with spark arrestor.... i dont know what is that. FMF XR50 Power Core IV Pipe for CRF50 - FMF - Pit Bike Parts Pro Circuit t-4 Pro Circuit T4 Exhaust - FREE SHIPPING BBR D2 Big Bore BBR D2 Big Bore Exhaust System for CRF/XR50 - FREE SHIPPING I'll buy it from local shop not from internet. Thanks.