Theon nailed it, check your squish clearance with wire solder & calipers or a micrometer. Torque your head to 120 inch pounds first(10 foot pounds). Bend the solder into an "L" shape & insert it into the cylinder through the spark plug hole, turn the engine over by hand (might need a wrench or socket on the magnet rotor bolt) until the engine turns over once. You want to squeeze the solder between the squish ring of the head & piston, it may not want to but this is cruicial to determine if you have sufficient clearance. Ideally you want .016" (according to Gordon Jenning's 2 Stroke Tuner's Handbook), but Fred of CR Machine says .010 to .040" is fine. The tighter it is, the more compression it will make, and more power. Less than .010 will result in piston/head collision from heat expansion & we don't want that. If its too tigh,t more gaskets may be needed, either an extra head or jug gasket. If its too loose, hand lap the jug and/or the head.
A Jaguar or Lightning CDI is a good idea, they have better ignition timing curves than stock. Upgrade the spark plug with a NGK, plug wire too if you can. I use an old MSD 8mm plug wire recycled from a tune up I gave my Chevy, definitely improved the starting & ride smoothness. You may find the increased compression a bit harder to grab the clutch, so an adjustment to the internal spring & flower nut may be required. When I upgraded my head to a Puch HiHi head, I went from a NGK BP6HS to a cooler BP7HS plug. I also installed a rocket key under the magnet rotor to retard the timing, made it run smoother & reduced my vibrations a lot. I would upgrade my CDI if I could, but my Super Rat uses a 1 piece magneto, so I have to use old school tricks to tweek my timing.
Other upgrades you might consider are shaving your piston & porting the jug, the only cost is gaskets and an investment on a Dremil. Do your research first, if you remove too much material you can't put it back & you end up with an expensive paperweight.
The best upgrade you can do is knowledge. Here's a link to free downloads of Gordon Jenning's 2stroke Tuner & Graham Bell's Performance Tuning.
http://www.scootershack.co.uk/threa...handbook-by-gordon-jennings-pdf-manual.25450/