AndyF sorry to hear about your crash -- first flight OOUCH!!

The 3W metal cap and the Bosch cap are one in the same. A shielded metal cap covering the exposed spark plug reduces R.F.I. A rubber cap does absolutely nothing but the plug lead is still shielded and grounded. I figured if 3W uses the Bosch cap in its original equipment, why not go for it. By the way it's $14.95 more but I had to send my original ignition supplied by BME (it was never used) back to C&H along with payment. There is another way but it involves buying the kit ($21.95) and installing the new cap and plug lead.

website: www.ch-ignitions.com