SRF is around $100 a litre trade price.
One big thing with ducting, particularily in you have the deflector mounted next to the hub is to check you are getting even cooling across the rotor. Next time after you come in after a track session, if you have an IR temp gun, measure the inner and outer faces of the disc, to check if they roughly in the same temp region.
Poorly setup ducts will direct too much air onto the face of the inner side of the disc, instead of into the hat so it can cool through the vents. one side of the disc been too cold will cause severely uneven pad wear, and reduced stopping efficency.
We run a variety of different setups, from stock brembo f50 calipers with project mu rotors, right up to AP, Alcon, and Brembo forged setups. A cheap way of stopping heat transfer from the pads to the fluid if you calipers don't have vented or titanium pistons is to track down a set of titanium shims. They can be had for a little over $100 dollars, and can be had for most common pad shapes.
If your at superlap this year, i might see you up there, we are entering three evo's this year, which should be good.