The steel gears have a different pitch to the fibre ones (steel have more teeth than fibre), so you'll have to replace both of 'em.
The supercharger will probably be from a low-mileage Toyota 4AGZE engine. They can flow a lot of air, and are nicely made. And cheap. Around the $400 mark complete. Intercooler is from a diesel Range Rover.
Brookfield only modified the combustion chambers to un-shroud the valves and smooth out the flow path a bit. He cleaned up the ports but didn't enlarge them. Otherwise it is unchanged. It seemed to work pretty well on the B20B it was fitted to. Damned thing revved like a bike engine :) Drop by with 20 bux in hand and its yours.
(BTW, John Brookfield was one of the blokes responsible for the development of Jack Brabham's Repco BT?? F1 engine way back. He lives down here now)

Steve