In June of this year I sold my G2 and purchased a 1979 P210 from Canada. The process is not hard, but it is involved. HIGHLY recommend Insured Aircraft Title Services (ask for Megan). They have forgotten more about the process than I care to know.
You’ll want to be sure that no “Canadian STC’s” were done (probably unlikely in Cirrus, but definitely a possibility in an older Cessna). They are verboten in the US. Must be completely removed before import.
You’ll need to deregister it in Canada and then register it in US. Megan can help. If you’re financing, it will take cooperation between buyer and seller (and bank). There is a period of time where the aircraft is in “registration limbo” - and some sellers freak out about that (because if, for example, you were to bale out after they notify Transport Canada of the dereg, they’ll have to jump through a bunch of hoops and spend money to re-register it. You’ll need a relationship with the seller to get this done.)
You’ll also need a DAR (or the FSDO) to sign off on a new CoA - which in all likelihood means and complete annual inspection.
Canadians use “Journey Logs” and you’ll want to make sure that you can tick-and-tie the whole history of the aircraft together (because you’re going to have to tell the story if/when you ever go to sell). Again, probably not a big deal on a newer Cirrus. For me, it took hours and hours of work to pull it all together. The confusion of multiple US owners, engine replacements, STC’s, etc., etc., etc.)
Reserving and N-number is easy and can be done for $10 on the FAA website. Google “reserve an N-number”.
Not sure what your plan is for pre-buy, but know that if you insist on an American inspection (as I did) you must get a Canadian pilot to ferry it down (and back if you reject it). Work out who pays for what and all the “what if’s” ahead of time. Trust me.
PM me if you want to chat about it.