Well, I can't answer all of your questions, but I can tell you the heatsink for the Lehner will depend on the gearing and size of the motor you select. But the short answer from my research is that you will not need a heat sink. Especially with the hi-amp because it will run cooler. I'm sure someone has a way better answer than that. :005:
You might check the thread I started on this Neu vs Lehner deal for my upcoming CRT conversion. Here's the link:
http://www.rc-monster.com/forum/showthread.php?t=5611
From what I understand, the Lehner motors are some of the most (if not THE most) efficient motors on earth.
Anyone else have some better info than me here?:027: