Looking into getting a parts bike

[Sean]

Ok. My buddy has a 93 bandit that he's willing to sell me. I have a 91. What's the difference in the engines? I know the 93 is detuned is that a cdi thing or is it physically different?

[phoenix]

I'm guessing you're talking NA market bikes?  Europe and Japan could have significant differences in wiring, suspension, controls, and brakes depending of it it was a local market or "grey" market bike. 
Engine should be the same unless one has the VVT and the other doesn't.  Design refresh was in 1995.

As for restricting, I saw two different types of restriction in Japan.  One version had tabs in the carb top hats restricting the amount the slides could move.  The other type was electronic in the CDI box.  In gears 5-6, the rev limiter was dropped a bit to keep speeds under 180KPH.  I ran a MMax derestricter while I was overseas, but pulled it off in the states.  Now it sits on my work bench as a piece of nostalgia.