the early 3.0 mitsubishi engine was known for dropping valve guides, which caused a smoking issue and oil usage.
as to the timing belt, i've only changed a couple over the years, but they were in minivans. wasn't a hard job, just time consuming.
while you are in there, change the water pump as well as any idler pulleys. [i can't remember if there are any in there like a 3.5 engine]
i don't know if the clearances are any tighter in a stealth vs a minivan. it might be a good idea to pull the hood just to see better.