that servo is rediculous for a 10th scale car. id go with a 1257/58 or even the 1251 as thats a very popular choice for touring cars.
they also have lower models without metal gears in the $40 range but for the $65 a 125x will cost i wouldnt bother with cheaper.
your motor/esc is just fine. any 10th scale electrics will drop right into the chassis, just a question of what batteries will fit in the battery box. if its anything lke any other tamiya ive seen they still optimize for stick packs, so i wouldnt get anything higher than 4000mah lipo. the turnigy soft case ones seemed to fit pretty well.
I personally wouldnt even trust any of my gear to a flysky or bargain radio..
if you can spring the extra cash, amainhobbies.com is selling spectrum dx3s right now for $169 with two rx i think? REALLY good deal for a starter radio.
a xerun v3 is probably a little overkill for non race cars. im sure their 80 amp xtreme stock or similar units would work great for the car. save yourself $100.