If I had a way to measure the temps, I would do it.
There's already a gap of around a 1/4 inch between the coil pack and the timing cover to allow air to pass between the two but the insulating plate should also help reduce radiated heat. Hey, for $35 shipped, its a nice, simple and painless add-on.
I have this spacer on my 12V Turbo. Nice fit with the new bolts that comes with the kit. 7 year old Beru coilpack and mk4 12V cabels. Up to 30 psi boost. No issues.
2012 Skoda Superb 2.0 TDI avant: Daily family car
1996 Golf MK3 12V Turbo. http://forums.vwvortex.com/showthrea...er-VR6-T/page6
2007 Mini Cooper sport: Dailydriver
You can get a smooth, quiet, floaty car and fall asleep waiting to get from point A to B, or enjoy getting there.
To be good at racing, you have to change your name to Sebastien.