You don't need the above Astra mounts because your Coupe comes with them. You can use the normal turned down front big block hub flange, you also need a ABS ring on the N/S front shaft for the speedo. To convert a C to 308mm Astra brakes use the carriers from a Meriva VXR. The expensive bit is getting it to the spec you want, I've spent loads and I haven't even got a Corsa to bolt it to. I'm sure if you post your looms to Warren, or Ben G they will do it for you.