The CDI boxes are the same on both but there ARE differences , there are large and small boxes, the large body one does run better they have a two digit number at the bottom of the part numbers on the epoxy, the higher number the better, they are all different I have seen a lot of them.
the tach is originally intended for racing go carts, takes a 9 volt battery and just wire ties to the plug wire. mine is a digitron but autometer makes an analog one also. The digital one also has a head temp. sensor, I got mine at a swap meet
I have one of those on my racing go-kart. Those things can cost a pretty penny. Dont expect a cheap ride here. But they are very nice. They even have backlights in them