depends on what you are wanting?
triggers, barrels, stocks?
Dlask is nice for barrels and receivers and misc parts.
if you want kidd stuff only 2 places in canada import it, Joe Brooks and Fabarms.
you can get VQ stuff from MilArm in EDM and also from P&D in EDM as well, P&D will actually order in whatever you want but it takes a while.
Wanstalls carries TS stuff which is good.
they also carry TI stuff which is crap.
not all brands mix or play nice with other brands.
your best bet is to try to stick to as much of one brand as you can. (my personal experience)
your entering a fun hobby my friend.
i hope your pocket books are deep!
my last 2 total custom builds.