Originally Posted by Craig

That is a good question. In my case, the reman IP made my engine run smoother than it ever had since I bought it (with about 150K miles). I just don't see the point of putting a high mileage IP on a fresh engine, the performance probably wouldn't be optimum.

I do suspect that a lot of the shaky/smoky issues on high mileage engine are (at least partially) IP problems. Even though they rarely "fail," I do think the degrade and affect performance.