I believe the only thing you'll have to do is use adapters for the speaker wires or cut off the stock Honda plugs and use standard clips in place. Either way will work.
As far as powering them, it shouldn't be a problem. The Infinity 6.5s say 2-60 watts RMS, 93.4 db sensitivity; the Infinity 6x9s say 2-100 watts RMS, 94.7db sensitivity.
From what I've seen on Crutchfield's site (browsing various speaker specs), the stock system will drive them alright. However it'll drive the Boston Acoustic 6.5s (65RC) and 6x9s (S95), both 2-way speakers, right at the peak RMS wattage. Since they're almost the same price (Infinity = $99 & $129, Boston Acoustic = $119 & $129), if you're sticking with stock power then those might be the best bang for the buck.
