My daughters 04 Stratus has just over 160 k and still climbing.( I bought it with just under 150K )
I just did the water pump and timing chains in it 2 weeks ago .

clean as a pin inside

IMO, at about 80K do the water pump and chain and guides kit ,,,, use full synthetic oil and you will be fine.
To do it yourself its about a $500 job (with quality parts)
figure in the 1k range if paying someone else to do it .


Look on craigslist, its not hard to find a 2.7 car with over 150K on it at all.