When I've read about the two missle types, the story of the HQ missle is that it started out as a cooperative project between the USSR and Red China, but in the midst of everything the USSR ended its cooperation and withdrew its technical staff, and the Chinese finished their HQ-1 missle by themselves.

I note that Trumpeter makes an HQ missle carried on a tractor-trailer, but no launcher pad kit that I know of. Also, how does the HQ differ from the SA-2, since there would naturally be some design differences?

There may be some minor differences, but as far as I know, the HQ-2 is pretty much a direct copy of the Guideline (i can't remember which one, but it was one of the shorter range ones, maybe "F").

The main difference in the weapon system as a whole is that the PRC uses a homebuilt radar. The upgrades have all occured on the radar/electronics side, the missile, I believe, has stayed pretty much the same.

For modelling puposes, I think the only difference is that the stencils would be in Chinese!

Here's a good PRC reference: http://www.sinodefence.com/

The two Trumpeter kits are basically the same. The only difference is in the trucks. The Chinese HQ-2 has the Chinese Jaifang C-30 tractor, which is a Chinese copy of the Russian Zil 157. The SA-2 has the Russian Zil-157 tractor. The two trucks are different in the grill and front fender designs.

Here are reviews of each from PMMS.

SA-2/ HQ-2 Missile on Transport Trailer

Zil-157/Jaifang C-30