I sold a friend an mpi supercharger for a stock 660. It made great power, really unbelievable. The clutch was the problem then. It would just smoke the wet clutch. After the pdm race clutch install it hooked up and ran good. Lots of heat though. Had to do a owe radiator and oil cooler and it ran much better with a mikuni 45 vs the stock cv carb. Bigger exhaust helped too.
To get set up as a dealer with mpi I had to buy 2 of them. I still have the 2nd one new on the shelf. I'm in it 3700 and can't get 2000 for it. They just don't sell.