The reason the twin power idles so well is because it uses a transistorized ign circuit for the lower rpm ranges (which has a far longer burn period compared to CDI) even when CDI is utilizing multiple restrikes at stupid high current and voltage it will never match the clean burn and stable burn ability of Transistor ign system and especially boosted ones.
Here is a plot of a custom CDI system I engineered/tested, its of massive output and specification, but still a smoke packet sized HKS unit outshines it at low engine rpm
Burn time is roughly 420us or .4 milliseconds and there is 6 separate restrikes at 1000rpm over roughly 5 milliseconds per cycle. System pulls about 25 amps of first spark and 13 amps for the restrike sparks.
Even at high rpm's and mid range the only time the CDI will shine is under high duress (heavy AFR and water injected for example), though many people can complain of a power loss on CDI systems. You only need to look at current F1 technology its a 50/50 split between CDI and Transistor systems! The HKS box employ both systems in their tiny case.
It is s great unit.