What flushmate unit will fit my kohler toilets?
These are the Kohler models that a Flushmate will fit:

Kohler
Worldwide
BARRINGTON™ PRESSURE LITE®  K-3578  Two-Piece   Elongated Raised Rim    Floor Mount, Rear Outlet

Kohler
Worldwide
HIGHLINE® PRESSURE LITE®    K-3519  Two-Piece   Elongated Raised Rim    Floor Mount, Floor Outlet

Kohler
Worldwide
SAN RAPHAEL™ COMFORT HEIGHT™ PRESSURE LITE® K-3597  One-Piece   Elongated Raised Rim    Floor Mount, Floor Outlet

Kohler
Worldwide
WELLWORTH® PRESSURE LITE®