When one of my Bosch coils failed on my 850csi I decided to see what was available besides stock items. The original Bosch coils are rated at 10,000 volts and best suited to firing copper plugs. I want to run iridium plugs so an upgrade was needed.
I settled on M70 Nology Pro Fire Coils (from US) rated at over 45,000 volts, Magnecor 8.5 KV85 Ignition Wires and NGK ZFR5FIX-11 Iridium Plugs.
The coils had to come from the US as no one in the UK has them.
I bought the ignition wires direct from Magnecore UK, they are based in Applbey Magna, leicestershire (01530 274975)
The coils fit perfectly on the stock mounting brackets with no modifications needed. The ignition wires won't fit through the stock black plastic tubes/holders so needed something to keep them off the exhaust headers.
I used 10mm stainless steel round bar cut to the same length as the original plastic holder and welded a couple of fixing lugs made from 30mm x 5mm stainless steel bar on in the same place as the original plastic fixings.
I used 10mm wire separators on the ignition wires and to hang them off the stainless bar.
I've done a couple of thousand miles now and all is working great.