Jammin` pipes
#2
JP4 is EFRA approved..
#4
The JP4 has the feel for a high RPM type of application. The JP3 feels good and good performance for the entire specktrum of what ever type of motor. I have them both. My motor in my truggy is the RB C6BB7 .21 and the JP3 works great all through the powerband. I use my JP 4 for my RB 928 .28.
The better of the two is the JP 3.
The better of the two is the JP 3.