Be very careful with this "hard shift" you're looking for. That is a lot of strain on critical parts in your transmission. I've spoken with mechanics and transmission specialists and they all advised against installing a shift kit because of that harder snappier shift, without upgrading those crital parts. Such as your differential and your clutch packs. Start blowing those things and you've got problems.

I may be narrow-minded but I'd say dont use anything other than MOPAR ATF+3 or ATF+4. Not dexron or mercon, definitely not.

Hope this helps you somehow, least in being careful with wanting harder shifts. MIght start breaking shit!

Joseph