Last time I changed plugs I noticed oil in a couple of the spark plug holes on my front cam cover. I am going to change the o-rings and cam cover gasket in a few weeks when I do the plugs. Does anybody know of anything else I may want to order for this job that as long as I am taking the cam cover off? Also, exactly how difficult of job is it to do this? Also, is there an aftermarket source for o-rings and gaskets which may be better than OEM?