U-boat,
I have built the Panzer IV and it is a good runner out of the box, and even a great battling IR tank. I did replace the stock TUs with Impact ones and rebuilt them with the Tamiya gears, and added ball bearings on the shafts with stock motors and 10T pinion gears. It is scale speed and runs metal Impact Tracks. There is a build thread on this forum:
http://www.rcuniverse.com/forum/m_95..._1/key_/tm.htm
I hope you enjoy the thread, I do have the Panther Kit but have not built it yet. So i can not say how it will build out, but I know a lot of guys that have them and swear by them. But I like the little Panzer IV it is a great kit to build.
Just my 2 cents.
Will