I recently had excellent dealings with a company in California called V12icpack.com.

My issue was random misfire on all RH bank cylinders. Spark plugs and both ignition coil modules had been replaced about 18 months ago. Turned out to be an issue with the ignition transformer unit.

V12icpack offer ignition coil modules and ignition module transformers as rebuilt units and have a service to test suspect components or will ship to you a unit to test on your car.

I got good service from these folks- fast processing of my orders and quick shipping at reasonable pricing. If you are having issues with random misfires on your 12 cylinder, you might want to check out their web site.
/HenryC

 

Good to know. I needed a transformer and couldn't find anyone rebuilding them.

Found a good used one on ebay.

 

A local place called Programa can rebuild them, they used to do the coil packs as well but ran into an issue with getting good quality components so they stopped. The trasnformers they still do though. Nice guys, have done a couple ECUs for me for other cars.

http://www.programainc.com/