Thanks for the comments and ideas. Here I try to answer all your questions together;
1. I ordered the tank from taobao.com in China as I have good relation with people there. Buying things from taobao.com is usually very tricky so I just ask the Chinese guys to help me, and they can also do the shipping for me. The RTR tank costs me around US$700 plus another $30 for sea freight. It took 4 days for the tank to arrive at shipping point and another 5 days to arrive at my home.
2. The electric of the tank is Clark TK22 (I believe you guys recognize it). The remote control is a Mato's 4-channels. When I confirm the order, the advertisement states a 6-channels one but after that it change to 4-channels very quickly. I complained to the dealer as well as Mato (on his youtube post), they gave me the same answer that the 6-channels has been discontinuous and the new 4-channels is better in quality. The Chinese guy asked me if I want to cancel the order. I said OK la, let it pass. I think this TK22 board is rather old and outdated. New board today requires at least 5-channels. The CS-TK16 I have support up to 8-channels.
3. Yes, this is the tank I am looking for; however, I think it would be better if I keep it unpaint. I knew from the beginning that it's a non-smoking version (smoking is not good to health). As you can see the internal space of this little tank is really limited. There's no space for the smoke unit.
4. I read the complaints of the unlucky guy with two Mato tanks. Someone asked Mato if they will produce the Tiger 1 late production, and the answer was yes, it's due to come out next year with torsion bar suspension. Actually my first choice was Tiger 1 but with many criticism about its build quality and inaccuracy, I turned to this Pz 3. I tested drive it on floor, it run smooth and plenty of torque. Have not had a chance to run it off road yet. My two previous Heng Long tanks (Pantiger and Leo2A6) have the same problem --- once running off road, one of the track will certainly fall off. I tried all I can do but problems never solved.
5. This Pz 3 doesn't come flaw free. First, the barrel is not straight (as the unlucky guy also complained). I bend it with hands trying to make as straight as possible. Secondly, the rear most road wheel on the right side seems to tilt inward. it almost touch the screw nearby but it runs well. Third, the road wheel next to the rear most one doesn't fall down when I lift the tank up. I think the correspondent torsion bar doesn't work. Do I need to disassemble the tank to deal with all the problems I found? Maybe, but not now.
That's all the problem I've found with this new tank. After I take the tank off road, I'll post video for you. Here's some photos of the problem I've found.
(rear most wheel tilt inward)
(the wheel next to the rear most wheel doesn't drop down, suspension not work?)
(finally, the tank sits where it supposes to be)