I think the X-ray would be the most competitive, either that or try looking into the Serpent S400.. Thats pretty amazing as well..
Once you have the car, its only a matter of getting to know how it works and why it works, which is not as difficult as you may think.. So long as you have a group of friends you race with, im sure they can teach you a thing or two that will make you better at it.. The forums here also have a HUGE deal of information you can learn about your car, how to take care of it, and how to set it up well..
Rubber tires if im not mistaken are the legal specs for electric car racing. Foam tires have much more grip on road surfaces, but they are more towards nitro racing cars. Rubbers also last MUCH longer than foam tires would..
I dont know much about carpet racing, but if you are going into 1/10 EP cars, i think its more worth it racing outdoors on tracks near you..
As for radios, it depends on your budget really. For beginners, try to get something that uses Spektrum waves (2.4ghz). This means there will be ZERO interference with your signal and no one will interrupt the signal between you and your car no matter what.. AM and FM frequencies can sometimes clash with other drivers if your frequency is not choosed properly..
If you have the cash, go for something like the Futaba 4pk or 3pk, or also a Sanwa M11. Those radios cost alot more, but there are worth it. Radios are something you can keep with you for life. The Sanwa M11 comes with a set of servos as well, which makes it a good deal..
For a little less, you can get a Spektrum DX3R, which feels really good in your hands and can do just about everything those other radios can do.
For a little less than that, you can try looking into a Sanwa MX3.
Hope that helps a little,
Mugen Seiki MTX-4R || LRP Z.12R Spec 4 || LRP Pipes || Spektrum DX3R (Coming Soon) ||