[thstone]

In a racing weekend, I shift near/at redline around 400 times (basically every upshift). Probably 10 shifts bounce off of the rev limiter. Then I do this 15 weekends a year; so 6,000 shifts at redline per year for the past two years. And I do this on a completely stock 2.5L engine with original IMS bearing and 97,000 miles.

Of course, this level of use is hard (very hard) on the engine and I expect its life expectancy to be greatly reduced (which is why I have a spare engine in my workshop).

But the point I want to make is that these engines are pretty tough and durable (despite what you might read) and running your engine to redline a few times a month isn't going to hurt anything or reduce its life expectancy.

With that being said and to directly answer your question, the engine will feel most alive from 4,000 to 6,000 rpm without placing any undue stress on the motor.