the RTR kyosho looks pretty good for the money, though, not sure how much you will get out of resale of electronics. I would say maybe $50 if you are lucky? Figure that in with the cost difference between it and the race version ZX5 (non SP). The ZX5 (non-SP version) can be had for $210 as well since the new SP version is out. From what I have been reading, its a good car, and for the money would make a good starting point. I would give it a strong consideration. Starting out, not sure how much of a difference you will notice between the ZX5 and the ZX5 SP to justify the price difference.
For durability and performance, the Academy SBV2 Pros (not the regular) are really up there. The 2wd GV2 version also appears to be quite durable and is a great performer.
The B44 from what I have read lives up to its BJ4WE roots which is great. Only thing I would have an issue with the car is the whole saddle pack deal but thats me as I like lipo. Other than maxamps, I am not sure if there is anyone else with saddles out at this time. And with the whole roar hard case rule, curious if maxamps stuff will be legal?
As for the question 2wd versus 4wd, with the 4wd you can put more power down since it is 4wd, and its easier to drive. You will how have more maintence because of this, more moving parts, faster speeds equals more chance to break something etc.
I would say the first thing to do is go to your track, and see what the turnout is for the various classes. Based on that, if 4wd has enough support that there are regularly at least 2 heats full (assuming a heat is 6 cars) I would give it strong consideration. Reason I say two heats instead of say one large heat is that with everything, people can be fickle and will move in and out of classes. If there is a good amount of people in a class, you can figure with people moving in and out, it should still be well supported. It would really suck to plunk down money in a wheeler and when you start to race some group of guys quit, and now the class is defunct or worse, you get a 3 man show which for some reason, SOMEONE ALWAYS BREAKS!
Now, after you see how the classes are, assuming they are both supported, see if anyone would let you wheel there vehicle for a bit to get a feel for the class. The main thing you will notice different between TC and offroad is that traction can change alot on the track versus TC which is mostly consistent, compared to what offroad offers as well as how setting up for jumps affects your drive line too. Also, when running 2wd, you will find that you have to be much better with the throttle control. This can really help improve your driving skills, or, drive you mad
I found offroad much more challenging that touring car, which is why I still do it.
As for the power you plan to put in the vehicle, I would seriously go and see what is common in the pits as what you stated even for 4wd would be excessive in my opinion but who knows, maybe the track you are looking at can take that much power and let you put it all down. I would be highly suprised if it could, especially for 2wd. A good common brushless setup would be like a novak 7.5 or 6.5 , or if doing the sensorless thing, a 4600 or 5700 setup.
with all that said, buggy appears to be experiencing a resurgence thanks in part to lipo and brushless I believe at least. Hopefully it continues.
Good luck with whatever you decide.