I am big fan of the Lightspeed Plasma III system. This is the third aircraft I've installed these on, and flown 1000+ hours without issue (...jinx...
However, there are certain parts of the system installation that I found to be sub-par:
1. Soldered on D-sub connectors.
2. Old systems - weird non-milspec wire from the flywheel sensor.
3. Cute but not useful mounts for the coils
4. #@!&* RG-400 for the primary wire leads.
#1 is easy to solve - cut off and use crimped-machined D-sub contacts
#2 replace wire with MIL-STD 27500, 20 ~ 22 Ga wire.
See attached for #3 & 4.
...and yes, adapting 2+Shield wire to a BNC connector isn't approved, but you can make it work and it's solid as heck.