i dont see in the listing neither monitor ,keyboard or mouse you will need those for sure + a good set of headset (for gaming)
something like that will last for gaming : https://pcpartpicker.com/list/cMPN7T just to have in mind a price .
his motherboard is UEFI .so should work with all cards.
pcie 2 Vs 3 not a big performance lost :
https://www.techpowerup.com/forums/threads/gtx-1080-ti-pcie-3-0-x16-vs-pcie-2-0-x16-test-in-8-games-at-1080p.256161/
my mistake just saw the canadian prices ,i didnt knew canadian dollar is so weak compared to USD.
i would buy the best in my budget + my system can handle it.
so for your case is : 1660 super/ti ,you will be fine with 1080p