well if you flush the coolant every year the coolant system should work fine for a very long time. the motor seems to run good till around 130k~ then they start to run into problems~ could be anything after 100k. I would also make sure teh coilpack/plugs/plugwires haev been changed every 50k~ and plugs every 25-30k or at least have their gap checked every now and then~
the 99 - 00 have pcv oil issues that put to much oil in the upper and foul out plugs so keep an eye on this seems to be the back two cylinders that suffer the mods.. easy fix get a catch cat to drop the oil out of the air as it goes to the upper's inlet or get an inline filter as I have to keep it down. in 01 they really fixed this but its still a small issue... not huge.
the auto tranny might start to get the shakes at idle around 40k a fluid flush every 15k miles should prevent this but once it starts its probably to late, flushing will only solve it a little bit it will come back (poor auto tranny upkeep)
the rear gears may whine but its just a factory thing~ not big deal just soem do some done, fixed in 01~
if you take care of it regularly you should not have any issues until 100+k so expect around then to start replasing this and that.
new motors are VERY cheap so even then it wont cost much to replace the whole motor lol 800 bucks drop in a 50k miles motor.