Hi guys, New to riding quads. but love it. Used to ride dirt bikes back in the day-about 30 years ago. Yep OLD man- New Ride... Anyway quads are great. I'm having a little trouble keeping up with my 16 year old son riding a Kawasaki 400 quad. Oh well, beats the hell out of sitting on the couch. I am looking for advice on some performance up grades to keep up with the kid. Any ideas on a slip on pipe and carb re jetting. I'm still up in the air about a slip on or a full pipe. My 400 has twin pipes off the head to a single at the muffler. Thanks for your time