I don't think I used any on mine, they mounted right up.
I'm betting you can mount up your old stock ones to your Magna though, maybe even your Shadow, that's when you'll need the spacers. I put my R3 stock shocks on the rear of my VT700. They work awesome.
Prog puts the spacers in because that model of shock is used on a variety of makes/models of bikes. Some need spaces, some don't.
FIRST!!! get a jack under the motor & support the weight. Then remove one old shock & fit the new one. Repeat other side. Remember that jack tho.. I didn'tops2:ullhairout:I had to lift the back of the bike up,( gets heavy when your holding it for like a minute:lol: & get the transmittion shaft past the rear footpeg bolt that it jammed below. Then hold the bike up while my mates slid weights under it to prop the engine.
Next one I did we used the jack lol.. just a whole lot easier!