I'm thinking the RHF3 would be a better bet. Ball bearing and water cooled center section.
http://www.ihi-turbo.com/turbo_RHE-RHF.htm
http://www.ihi-turbo.com/turbo_chart.htm
Looks like a guy used an IHI to build a li'l turbo bike, but the thread dies. not sure if it actually worked or not.
http://www.pocketbikeplanet.com/129-4stroke-midbikes/33439-turbo-pocket-bike-runs.html
those are some crazy bikes! lots of $$$ into them. gotta love them japanese tuners!http://power-flag.ftw.jp/u53063.html Takegawa 124 with turbo and keihin carb all custom and street legal. In japan the bike stock is 50cc and you register it at the Japan DMZ and pay yearly road taxes on it at the city office. No one checks it or sees it. Plus if you have a car license you can drive it.
check out the drag racers. Serious high torque pipes.http://power-flag.ftw.jp/u58308.html#dragthose are some crazy bikes! lots of $$$ into them. gotta love them japanese tuners!
EFI kits have been available for the last 2-3years for minis. Now honda makes EFI stock on the new supercub which has the same engine as the crf 50 and Honda APE which is the same engine as the NSF 100Piping is easy. the difficult part is getting the carb set up properly.
It looks like someone's got the first closed loop EFI system for a suzuki single up and running for the AMA series.
http://www.supermotojunkie.com/showthread.php?t=59285
Turbo Sumo kits aren't far off in the future. I give it 5 years, max.