My Opinion on what to get.
Okay, I'll step up and give an opinion.
I would go with an XRAY FK05. My experience with it so far is that it is bulletproof. So far in checking around, I have found that to be true among other Xray owners. Although it is pricey, it is a rock solid car with plenty of durability and dependability in handling consistently on the track with out a lot of constant adjustment or tweaking.
I considered other cars like the Yokomo BD and the JRXS. I didn't consider the RDX because I heard that parts were difficult to get and also more pricier than Xray parts which are already expensive. However, those whom I've spoken with who have one say its absolutely dialed out of the box.
Buy the car you like that looks cool to you and that feels most worthy of the many you spend for it.
My 2 cents