What weight hammer spring do you have in your Shadow 2? If it is less than 17# then you can expect some misfires with the Kadet kit.
The firing pin hole, breech face, and chamber will get very dirty in a few hundred rounds. Keep a dental pick handy to clean the breech face, extractor, and firing pin hole.
Just follow the instructions for installing, and it doesn't matter if the Kadet to frame rail fit is a little loose, you just don't want it too tight.
The magazines and Kadet conversion is really a first class .22 conversion kit. I have around 50k rounds through mine. I put a short piece of rail on the top of the slide and put an Ultradot sight on it for Bullseye. I believe the dovetail mounts for the Shadow are the correct ones for the Kadet, if you want to go that route.
Keep an eye on the barrel retaining pin. Replace it every 10k rounds or so. That's about it.
Joe