The OEM ones aren't that bad. They do a pretty good job even at stage 3 levels. The Nology stuff is not compatible.
The only thing that I've seen aftermarket that is compatible as a plug&play on our cars is this:
http://www.okadaprojects.com/usa/products_direct.htm
Honestly though, there are alot of OEM coils out there.
The S4 used a Beru coil and then had the Bosch ICMs bolted to the airbox. The ICMs are spark amplifiers and the coils just convert it and deliver it.
On the newer cars B6 A4 and C5 A6. They use either a Hitachi coil/ICM that bolts onto the valve cover or a Bremi coilpack/ICM that pushes into the valve cover. This type of unit actually will make a stronger spark and can run larger gaps without misfires. They Bremis are also under $30 each. The current revision is "R" and they are supposed to last longer than the older versions. My car came with "L" versions and they died 200 miles after chipping the car. These "R" packs are much better. The Hitachi packs are very good, you just want to get the "E" version. ECS sells them as a kit.
It is possible to convert your wiring to use the Hitachi packs. I saw a writeup from Jeff Lee on this a while ago:
Here.
This is for converting the older A4 coils (Beru Style + ICM) to the newer Hitachi coils with no ICM.
Bookmarks