So just to be clear, I will need to spend some extra dough to calibrate my speedo w/a mega short? Drivetrain and gears are stock, but I've got the 33's...
who's mega short are you using?
either way, i'm pretty sure all of the "short" SYE's use a tone ring (like found in rubicons) instead of a gear. the spedo signal will transmit to the speedometer guage, but will be off (IIRC back to stock spec).
you would need the speed-o-healer to correct the signal. (there are other options, but the speed-o-healer seems to be the most popular with jeep guys.) so its not something that would have to happen right away. but to do it right you would want to.
the nice thing about the speed-o-healer is you can adjust it (on the fly i believe) easily down the line when you go with bigger tires and/ or re-gear. so no need to buy new spedo gears anymore.
i looked into all of this recently, but decided that a regular SYE would suit my needs b/c I dont plan on swapping out my 2.5OME lift for anything taller.
again, there are advantages to the "short" SYEs. with 4" of lift and a TT you will most likely want one. so set yourself up properly from the get go and save your pennies for another month or two.
so you probably dont need one with your current set up, but down the line....