I'm not sure about the differences on the 2 running characteristics,I always check my gaps though.Some need to be changed some don't,It's just like a car they say they are already gapped but it's just a little extra insurance for me to double check ever time I replace a plug.
I don't think the .008 difference is really an issue,I have a good spark at .025 so I will continue to run them there.Hope that helps. Terry