the maintenance light is literally just on a mechanical timer. it's purely a reminder that the 02 sensor should be replaced every 75k miles (and so it pops on after 75k and then you need to replace the timer itself which is the clear thing with all the gears located under the dash). it has no other function. you're thinking of the OBD1 system that started in 91 with the HO.
the cheapest aftermarket speakers available are better than the factory. can't go wrong really. but if you feel an amp is in your future, then you need something worthwhile.
got my doubts, but anything is possible. the chief stopped existing after 87. but then all it would have taken is a guy at the dealership ordering a chief hood sticker pack. heck, I have one up on my wall.
factory MJ rear shackles are longer than factory XJ rear shackles. but they are the same width and thus interchangeable. but an "XJ lift shackle" will not give the same lift if installed under an MJ. 2000s Chevy 1500 truck "2 inch drop shackles" (they are inverted on a chevy and so longer ones lower the chevy) are usually the ones people go for. very cheap and you can get them at most any auto parts store.
you can do a 2" puck up front, chevy drop shackles in the rear and not have to replace any other parts. an alignment is recommended after any changes in height.
the rubber seal on late model XJs is essentially glued in with the glass. if you get a new windshield and tell them it's a 98, they will bring a new rubber trim with it.
I love it when I need a thing and then find that thing i the parts pile.
be sure to add the dealership sticker to the thread about them. wherever it is. lol. probably in the pub?