If you are that worried about air starvation at higher RPM's, you can always go the 'flap route' similar to what Erik in Scandinavia did. He essentially took a 1 gallon plastic bottle, cut out a flap, and used that to restrict the air flow on the right side. When RPM's increase, the flap sucks/folds inward, increasing the intake area for the airbox.
Dunno how well this worked for him, but he seemed happy with his results.
I can tell you that at an altitude of 4250-ish feet, with about 1/3 of my airbox restricted with foam, that my Connie is much better behaved at lower RPMs, and has more torque. I can actually tool around at low speeds in parking lots without worrying about 'rpm surge' as much when I nudge the throttle. One time, I was stuck on the freeway at 0-10 MPH highway speeds, and simply used the clutch to modulate my speed, without even paying attention to the throttle. Pre-foam, I'd have to worry about killing the bike if I wasn't careful, with the foam in place this concern went almost completely away.
And this is with the 'stock' Cali jetting! I did take a slight MPG hit (I get mid 40's, so anything out of the ordinary, such as getting throttle happy, affects that number), but I felt it was worth it.
The only time I've noticed an issue with the foam and stock jetting is when canyon chasing at higher than the recommended speed. At those higher altitudes, I did notice a slight lag around 7000 RPM, and removing the foam did help with that lag. The beauty of the foam, though is (if you have the thumbscrews for your side panels), simply pop off your side panel, and remove/replace the foam. Takes about 2 minutes to modify, and NO TOOLS!
That being said, no one is holding a gun to anyone's head to use Steve's jet kits. If you want to go another way, you are of course free to do so. And if you can stumble on the perfect jetting for your application, that's great too.
For many of the rest of us, however, we like doing things once and getting results. Steve has now sold dozens of jet kits to people on this forum, and pretty much everyone that has installed his kits has said 'more power, more torque, better throttle response, better fuel economy', with the caveat that 'I'm now finding myself twisting the throttle more, as I'm enjoying the new power curve waaaay too much, so my fuel economy probably could be higher if I could just control myself!'.
Some of those endorsements have come from people in my area (Colorado, Arizona, and other states at similar altitudes). Unfortunately, with the forum conversion, we lost a few of those posts, so some of those aren't searchable now, although new endorsements have been posted since. The 2 minute mod has been around for a couple of years now...
With all those endorsements I've read over the last several years, and knowing how open Steve has been with his research efforts with us, and the fact he still hangs with us here and gives advice all the time free of charge, for me it's a no brainer. When I have the spare cash, it's 2 Minute Mod economy jets for me.
