Goodfellow,
I have NO experience with a forced inducted R3. But I do have experience with turbo'd 'Busas and 'Herdleys', and I wouldn't recommend this for 99% of the good riders I know. At 100mph, more than 50% throttle and you are looking at sky... very temperamental, and not fun in the twisties.
It is hard to beat forced induction for hp/Dollar spent, but this may not be what you really want in the end. With an easy 6-6.5% more hp per pound of boost, many wind up with more power than they really like to ride, and wind up short-shifting before boost comes on - but the power is available if and when you need it. The low compression and low cam timing R3 lends itself well to forced induction. The big thing is that the cost of the supercharger kit does not include the time (and money) spent tuning the system after it is installed, this is not a small project - ask Hombre.
Personally, I really like the idea of a centrifugal supercharger, like the Rotrex, on the R3. Air flow comes on as the revs climb, and makes this a controlled rush to the redline with mild manners at lower rpm. Compared to N2O or many turbo kits that come on abruptly, the riding manners for a centrifugal should be very good.
I feel that Vortech has a unit that may be really good for the R3's flow needs as well - it is just that no one has developed the mounts and drive needed - a fairly good job, but not too hard. This could be a good bit cheaper than the Rotrex kits if done right. It could be very compact if done with a water-air intercooler (mounted at the throttle bodies) like the very efficient Laminova cores. I have a box of these cores gathering dust in my garage.... Hmmmm. Or it could use E85 without an intercooler, but this may not be good for long road trips where E85 is scarce.
What a forced induction R3 likely will want (others like Hombre can add input here) is slightly taller gearing - especially at cruise speeds. The shaft driven differential on the R3 will make this an expensive proposition with custom gear(s) needed.
It all depends on what
you want in the end.
I have a good collection of superchargers that range through multiple Roots designs, centrifugals, Lysholm screws, turbos of various sizes and AR ratios (YES, Turbos are still superchargers), and even a Latham axial-flow. But most of this is for cages. Bikes are different beasties, and need to be treated (and modified) for the desires of the rider - most don't really know what they want, they only
think that they do.
IMHO, the R3 has more than enough displacement to make the torque required to terrorize the streets. The problem is that it is severely de-tuned and is NOT efficient - it doesn't make good torque/liter numbers. I think this can be easily solved - at less than the cost of a supercharger set-up.
Consider what you
really want the bike to do, and how you actually spend most of your time riding it. Then balance this with what you can spend without getting carried away or buyer's remorse (important). You may think you want a really high dyno number, when all you really want is enough performance to take on most of the local guys and still ride like you have been riding. There will always be someone faster.... always... ask John Force (who, by the way, is now relocating to NC).
Sorry about the book length post. -WT