I would look at DiodeDynamics. They sell a
much larger variety of LED strips and at more reasonable prices.
Those, however, are not plug-and-play strips like Subaru's seems to be (but I still can't understand a price that high for something that is not as complicated as the price might imply).
Either way, it mainly depends on how you plan on making them work (doors opening, fully manual switch, etc.) as that will dictate the installation difficulty.
Just measure your footwell (I don't know how wide they are), get the length and color that you want, and go to town if you want it truly matched to your taste.
http://www.diodedynamics.com/store/l...p-weatherproof