Sorry, I have not seen this thread in some time.
To answer Nurxhunter: Forced air should not be used because it raises the bias current. The amplifier, by design, seeks to reach equalibrium between temperature and electrical operating point. If you've ever had to wait for an amplifer to "settle in" for it to sound its best, it is because of this. As it is, the bias current of these amplifiers is quite high because of genuine class A operation, forcing it to go higher will shorten the life of the output devices because they will try to run hotter even though forced air may seem to make it run cooler. It was designed to be perfect without forced air - the huge heatsinks take care of that just fine.
You may also note that these amplifiers run cooler the harder you push them (as opposed to class AB amplifiers which get hotter) - that's because some of the power that is otherwise dissipated by the heatsink at idle is now going into your load. In other words, these amps run hottest during idle.