Re: Jag cdi
Just speaking in general terms here (and my background is with V8 cars) the products in question aside here, there must be something in being able to fine tune your timing to suit individual motors, 4 stroke cars for example, the factory always soft tunes cars, with no other mods, fine tuning the advance curve always improves drivability and throttle response, even more so, once you raise the compression ratio and or improve valve timing it is a must to alter ignition timing.
FWIW all the hard core bike guys spend hundreds on the best CDI to improve performance.
Two main issues are 1, spark strength and timing.
The higher the compression ratio the stronger the spark needs to be.
Timing needs to have a slightly different curve than standard and will, in most cases, need to be retarded at WOT with higher comp/rpm and improved port timing.
A standard unit may be suited to mass production but once you play with these things, head, compression, porting and the like then you will, in my opinion, need some way of improving the ignition and dialing in the timing.