Well, I always think it through, but I'll run the #'s past you.
New from Canada - $430 plus tax (13 %) = 485.90, then tune up $75 + tax = 85, then shipping or gas $40 for a total of $610.65
Buying used from US delivered to me for 290(US) (318 cdn) then to Sparky's say $120 round trip (when I have some extra $$$). All this $$ has not been put on credit card, spare $$ laying around at the time.
What I have found is that Sparky's is I think the best place to buy from, some items (for me) its better to buy used and have him tune it.