The TC3 and TC4 have some interchangable parts, some not. It would really be easier to go on a part-by-part basis than list them off.
As for "blinky" this means that the race does not allow your ESC or Speed Controller to advance the timing to your motor and gain the massive amount of torque and power that corresponds. It's called "blinky" because when timing advanced (also called Boost or Turbo) was the norm when you would set your ESC for non-boost it would have an LED that would blink... normally.
As for different classes and restrictions, in touring car they are typically by motor type, USVTA is the slowest with a 25.5 turn motor and a spec tire, "Stock" is typically a 17.5 motor, "Super Stock" is either 13.5 or in some cases 10.5, and Mod is any wind. The fewer the winds, the more torque and RPM and motor will have, with the highest powered cars capable of 60+ miles per hour in a 120 foot long straight, over 80 on a 200 foot long straight.
Personally, I would like to say welcome to the world of RC racing. Have a nice look around, and if you have the dedication and talent you just might be champion some day.