yes that is a d35 with reversed terminals BUT... it is a smaller battery. the d34 is the normal size that SHOULD be put in the X. but no d34 reverse terminal batteries are made anymore (in the yellow top)
just get the "non reversed" terminal battery and do the battery mod to it. Everything should work out dandy! I was the one who originally posted the battery mod and nothing has gone wrong with my X so far. Also if you want to check out Exide XDC batteries they are very similar to the optima yellow top (but you will have the same installation problems).