For the most part stock cdi will work better then most performance cdi's. Typically all they do it make it hard to start. I've had good experience with no rev limit cdi's and the ones you adjust are neat but don't always last. If you do buy a cdi be aware that there are dc and ac fired cdi's.
The hot coils are kind of in line with cdis' yes it should give you more spark if it's really what is says it is not just a stock coil with orange or red wire. My whole thing is if you can get one for ~$7 why not see if makes it run better. I've had some that work great. But they are always a point of contention. Some say they don't last as long as stock coils either. Here is one that should work for you from a great seller. The one you have above is for a gy6 the engine used in just about every Chinese 4 stroke scooter.
http://www.ebay.com/itm/281201847050