I certanly wouldn't say works perfectly. As I said earlier anything that cuts (or interrupts) the primary charge will fire that coil early.I would say the conclusions are, for $199 you can get a 2-step NLS box that works perfectly.
To give you an example, the factory coils charge about 2.5ms. An engine running at 7k rpms rotates 42 deg every ms. If you interrupted that coil charge a ms early you advance that cylinder by 42 degrees. That's enough to cause pre ignition type damage, and certainly detonation even with good fuel. With this platform moving to move powerful coils with longer charge times the effects will be even more pronounced.
The 2 step has a little less effect because of less loads and lower rpm but the same thing is still happening
You'll probably ask why we haven't "seen" a bunch of motors blown up from them, the answer is we probably have and it's blamed on other things like port injection or the tune ect.
I know of two local cars that have blown motors that were using NLS.