I've seen two Legacy aircraft on the market that are supercharged,
apparently to the level of making 25" or so at 15,000'.  Reported
airspeeds look good (260 KTAS at 15,000' and 15 gph LOP).

If anyone has experience with these installations, I'd be interested to
know about likely maintenance and operational issues.

They're manually controlled and not inter-cooled.

Craig