I am a CFI. The definitive answer is that a Flight Review
(14CFR61.56) is not tied to Category, Class or Type so do it once
every 24 months (in an aircraft...note rule does not require a rating
in the category or class) and you are set to go in anything you fly.

Flight Currency (14CFR61.57) is another matter. 3 takeoffs and
landings within past 90 in Category, Class and Type is required to
carry passengers.

On-line FAR's available he
http://www.access.gpo.gov/cgi-bin/cf...i?title=200547