What spark plug wires are you running on your SC?
 

My 3.0 probably has the original spark plug wires, and when the engine gets hot, it routinely drops a cylinder, which I suspect is a marginal spark plug wire.

Is anyone using Magnecore or HotWires, or any of the other performance wire sets on an otherwise stock CIS 3.0?

Magnecor 8.5

First thing I did when I got my otherwise stock SC was to replace the bad wires. Major improvement over the bad wires.

I replaced all my wires, and periodically I check the condition/function of the set and replace parts as necessary. Both ends come off, and the wire itself has a crimped-on screw connector that does require a special crimping tool. JW happens to have that tool, so he can make wire sets. The stainless steel braiding is not necessary. I removed that.

Many of the folks here are wild about the Magnacore wires. They're apparently very good right out of the box.

try NOLOGY HotWires

I tried the Beru wires on mine and I would get seriously shocked anytime I came near them. I went back to the stock wires and just fixed my connectors and everything is fine. If they need to be replaced again, I'll probably go Magnacore.

I have magnacore with good results.

Stock 964 wires. ;)

Tom