Compression isn't high enough to warrant higher octane. You may actually loose performance going with Higher octane than needed, it's harder to ignite versus lower octane fuel.
As far as the plugs go, we all need extra's right? Get the EK's and pull your current plugs out and use them for your spares. I'm not sure if you have an Advance Auto in Canada, but they have them for about $5.50 here in the states. You must have some large retail auto parts store you can try. You won't find a cheaper 2 HP increase. When I bought my RX-1 last year the dealer charged me over $6.00 for each of the oem cr9e's :x
