As an SLI 970 owner, I can say that I can't think of a worse bang for your Canadian buck purchase than 3x 970s. A third card seriously diminishes in performance add-on for another $465(CA) on top of the SLI $930 cost for a total of $1395. If you plan on 4K gaming, you are better off getting two 980Ti cards for $1680 http://www.newegg.ca/Product/Product.aspx?Item=N82E16814127895.
This is all excluding factors like increased power use and more heat output (good in fall and winter, and yet bad in spring and summer...may not be as much an issue in Canada though vs. someone like me living in the US Southeast).
Better yet, just wait four months for Nvidia's Pascal and see what they do for the 9xx replacements. If I were in the market for a new GPU only for an upgrade and not for a necessity replacement, I'd wait for Pascal.