200,000 miles is possible, but a 3.0 tends to stay stronger longer. As mentioned before the valve guides tend to go and that's the problem with our 3.2s. Many tests show that a healthy 3.0 with 100,000 still to this day can test at stock levels or even a bit better with no major work to the motor. A healthy 3.2 motor with 100,000 miles may test about 225-230.
Instead of being equal or above like the 3.0 they can be about equal or a few ponies short. Obviously motors not maintained well or tracked all the time won't see these results. But I do believe and have seen over 200,000 miles 3.2s running great.
As for the redlining it to keep it in shape, I am not sure. I've heard that many times myself and yes running hard and long will remove carbon deposits, so in that case its true. It may not be true beyond that but it makes sense to me. Cars should get a workout just like us
