I have a temp-gun. It's one of those small Dura Trax ones.

I did run the Quark today. My setup has changed from what it was. I'm now using a Neu 1515 1Y. Batteries are the same, 4s 7400mah lipo and gearing is 12/51. Before I was using a 540c 9L and I always had trouble with temps creeping up to 200*F and above towards the end of the run.

Look Mom No Fans!!!
Today went good with the Quark. It never thermaled on me even without fans. It does have a pretty good heatsink mounted on it with the front windshield completely cut out for air circulation. Temps stayed in the 125* range for a good portion of the run. It was pretty much all out non stop going for approx 20 min or more except for a couple of temp checks. Towards the end the temp did get up to about 147*, but it never thermaled. The motor was at 159* at the end. The outdoor temps were much cooler then a month ago when I started this thread. It was a nice 88* day.

One of the most notable things was the temps at the boards where the motor wires come out. In the past that area was generally 15-20* hotter than the heatsink. This time those temps were only 1-3* difference and they would even out within a minute or two. To me that was pretty significant. It tells me that the work I did may actually cool the internals better and more quickly.

Quark vs. Mamba
The Quark felt like it had a higher top speed. The Mamba felt like it need to go up a tooth. Punch seemed equal. Quark overall had a more powerful feel while the Mamba felt a littler smaller. Don't get me wrong though I love the Mamba, but for 1/8 if you can get the Quark not to thermal I think it is a little more suited.

In the end I think I may still have to run a fan on the ESC, but I'm going to push it and see what happens without a fan first.