some encouragement
Tron brings up a good point. Anything over about 36" (90cm) gets very expensive to ship.
So, local pickup may save you quite a bit of money.
The link you gave is for the Canadian distributor/importer, so there were no prices.
I'll assume you've verified you are getting a good deal.
While I don't have that dish, and haven't read any reports on it, there are a couple of good things to mention.
1). it has the side support struts on the LNB holder.
2). it has a big elevation adjustment screw.
Both are a major plus in maintaining and achieving proper alignment.
When you get the dish and before you assemble it, place it face down on a large flat surface.
Make sure the rim of the dish touches all the way around.
That helps test to make sure the reflector is not warped.
If it is, there are some tricks, but let's assume yours is perfect. - :up
There are threads on the forum about putting similar large dishes on little SG2100 motors, and while they don't seem to be a good match, we have folks who swear by 'em.
One thing is to get the larger 50mm replacement tube.
Since that's around $12 or more, some members just shim the existing motor tube with a piece of plastic pipe, slit up one side.
You should read threads here on mounting Primestar dishes on SG2100 motors, for more info on the subject.
Let us know as you make progress, and post pictures.
That'll get you plenty of help and encouragement.