You could do a set of JE Hi-comp pistons, balance the crank, lighten the gears and fit adjustable and lighter cam wheels.
Most of the lightening and cam wheels can be got through Mark at MADASL including some spaghetti headers if your budget stretches that far:
http://www.madasl.co.uk/products.php
This should make a difference with the FCRs.
Yorkie