The two minute mod involves stuffing a piece of foam in the right side of the airbox intake. I have the right side of my airbox blocked about 60-70% currently, which seems to work out pretty well. My top end performance has been lessened slightly, but I'm loving the increase in low end torque. The left side of the airbox intake is completely unrestricted currently on my bike.
The downside of doing this without proper jetting is that you will very likely take a slight hit in MPGs. My bike has always done fairly well on the MPGs in the 65-75 MPH range. I average around 45 MPGs with the foam in place, was about 46-48 before. Also, your bike will run a little richer, which you will probably notice when you pull the plugs out for maintenance.
You should also understand that I am at altitude (around 4250 feet above sea level on average here), and have several long straight roads on my way to the freeway, so not a lot of stop and go. Both of these help my MPGs. I also shift between 3-4K RPM, and run the bike in a relaxed manner most of the time (i.e. gentle use of the throttle).
I like the low end torque too much, so I've accepted the MPG hit for now, but when I hit the lottery, etc. I will of course get the economy kit from Steve.
Both of Steve's Jet kits have been noted to increase MPG's, with the economy kit of course giving a better increase in MPG's. Plus, the increase in low end torque is always a good thing, especially when you are tooling around at low speeds in parking lots and such.
R.E. your MPGs - which are on the low average depending on who you talk to, btw my MPGs drop down to around there above 75 MPH. If you haven't drained/flushed your carb bowls lately, it just might help, should you have some debris on your float needles and such messing with the metering of your fuel mix. It's fairly easy to drain your bowls, and who knows, it might help!
This did wonders for my bike, but then I hadn't drained my bowls in a while, due to the fact I run my bike nearly year round. I'm at 41,000+ miles on the odo now, and still haven't pulled my carbs, as I'm still getting decent performance/MPGs despite the factory jet settings. I also use Seafoam every so often as part of my preventative maintenance. Of course, if my bike sat for any period of time, I'm guessing I'd be due for some carb work by now...