I am fitting the Caterham roller barrels to my R400 duratec. Its an S3 with an early metric chassis. I am going with the foam air filter, not the big track day airbox as per R500. I want just a small teardrop-shaped bonnet cutout that follows the line of the airfilter. Arch will do the cutout, but require a template. Caterham only do the big cut-out, even if you dont have the airbox. Has anyone done this or got a template (or measurements) for the bonnet cutout for duratec roller barrels in an S3 metric chssis ? Thanks Angus