you don't need to grind down the bulkheads, however if you do want to use them you'll have to grind the battery slots. I reccomend (a la mark smyka) a 1" sanding drum kit, which can be found at the home depot. Chuck it into a cordless drill and just slide it in the slots. Perfect bevels in like 2min for the whole chassis. For my 04, I used a spindle sander with the same bits to do the standoffs so you didn't have to tighten/loosen them from the underside of the car for the bigger cells. Also, remove the foam from the straps.
Speed Merchant/Corally USA/Specialized RC/Team Kwik/Tekin/Sweep/Parma PSE/Team Pickles Performance