My manual N/A S60 RPM's are as follows:

70mph - 2,850 RPM's
80mph - 3,350 RPM's
90mph - 3,750 RPM's

I noticed while using a loner, S60 LPT Automatic, runs at much less RPM's at these speeds.

1. Does the 2.4M N/A engine should last less than the turbo? If it does, I made the wrong decision, because the reason I selected the N/A was because I though it was more durable. I use my cars for at least 10 years.

2. Does chipping the ECU helps reduce the RPM's at these speeds? I drive 60 miles/day averaging 80 mph. The car is virtually 100% highway driving.

The car runs absolutely great at these speeds, although it does not have the take off of a Turbocharged. Although I am not into the take off power, I enjoy high speed power, which there is plenty on this car.

The car rides really motivates me to go to work.

NOTE: I just remebered a car I used to drive, Audi 80, I4 whith similar RPM's at these speeds. I used the car for probably 150,000 miles with no problems at all, no oil consumption, and no compression loss though.