yep, E-bay is the best source for quality stuff. Guys sell there because whatever they sell is so good they want to part with it.

Your ignition misses can be a lot of things. Check your wiring. One line may be broken, and make intermittent contact by engine vibrations. Also cells connectors have been know to fail, switches loose steady contackt etc.
If all is OK, the ignition may be at fault. Put it in very soft foam and use no tie-wraps, but rubber bands to keep it in place.