i'd do the tranny swap too. i've driven one of those 4cyl/auto yjs and that combo is horrible. you will notice a big difference with a 5spd. additionally, i realize you can get the ax-15 easily, but look around for a heavy duty tranny with a granny gear. it might save you another swap further down the road. i've upgraded, and re-upgraded too many times...this is experience talking! think it through and go big, your purse will thank you later!