We've had three 2nd gen 2.7L Intrepids (about to pick up a fourth) and we've put a total of 350,000kms or so on them over the past ten years.
Frankly, I've been stupefied at their reliability. AC compressors have been a problem (they seize), but perhaps only in Canada or the northern States where they don't get much use. Two of them cooked their cam sensors and one cooked its crank sensor. One had evap purge solenoid trouble and one has EGR issues, but neither of these have caused any driveability problems. As far as running gear goes, I've changed a lot of tie rod ends, but ball joints, drive axles, brakes and suspension parts have all seemed to wear very well. They also don't seem to have the same subframe bushing problems as the 1st gen cars. Earlier 2.7s seem to burn a fair amount of oil, but our '04 never burned a drop despite getting the most miles. That won't be a problem with your 3.5, obviously...
Overall, with all of the time and miles we've put on these cars, that crank sesnor is the only thing that has ever kept one of them from running. One day of letting us down over all these years is pretty impressive! They're great cars, and they're excellent to drive.
