[shinytopman]

Hi Stu.
The Mac BTW is the Mclaren shell. I use crurved scissors to cut my wheel arches, have used a compass cutter but prefer my scissors take it slow and don't cut to the edge of the blades.

If you do get a rough edge just sand it down a bit to clean it up. Before attempting the wheel arches cut off all the flashing so your only trimming the base line of the shell and arches.

I also use magnetic body mounting guide (they sell them at Demon Racing) allows you to place the completed shell over the chassis then move it about till it's in the right place then mark with a sharpie and ream the holes.