Thanks WRX! I'll order the jet kit and then do it then. If I put on an exhaust later will I need to re-jet it?Don't do it unless you are doing the jet kit at the same time. The bikes run lean from the factory to pass emissions requirements, and that is with the little airbox opening. By enlarging the opening, the bike will run even leaner. Running lean means running hot, and could cause damage.
Do it at the same time that you do the jetting, it only takes 5 mins.
Did you notice a big difference from the 3x3 itself?I put 1,000+ track miles on my DRZ with the 3x3 mod, K&N air filter, and full Yosh system before I put my jet kit in. It ran fine for me. (I do not ride the street with my DRZ...so, the throttle is "wide open" 95% of the time)
To be honest with you, I was disappointed when I put my jet kit in. I could not tell much difference.
Street riding might be a little different.