[scarceller]

DO NOT just put any coil in the 84-89 911 Carrera, that DME has a dwell map optimized to charge coil to about 3.8milliseconds at system voltage of 14.0vdc and unless you are certain that the replacement coil has that same charge times you can overcharge the coil or undercharge it. Most replacement coils like MSD have lower charge times and you'll force the DME ignition driver into overload current protection mode, not a good idea!

The new silver coils are not as good as the old stock original black ones.
But the 964 coils are the exact same coils! So go hunt for a used set of 964 coils and you'll get 2 of them!

Bottom line is that to use an aftermarket coil you need to recalibrate the dwell map on the chip, you need to really understand the DME to do that. Just find decent set of 964 coils.

To the OP 'azhodge', Why are you changing the coil? Do you suspect the current one is bad? The stock coil setup is perfectly fine for a stock engine, you will gain nothing by changing the coil. Just be sure you are using standard spark plugs with gap set at 0.8mm. DO NOT use any fancy multi electrode spark plugs!