With each exchange with the inventor or review of the documentation, I become more convinced that this is not a "kit" project for which you can buy the parts and, voila, have an F.Y.P.
Consider first the servo connections. I know that is a dead horse at this time, but you really need to look at them.
Second comes the rpm sensor. As it stands now, if the car has a three-speed transmission, you need it, but if it is just single speed, then you don't. I didn't see anywhere in the documentation how one changes the gear (i.e., shifts) under remote control. Maybe that is the other black box that looked like a servo to me. However, consider that if the speed change is done manually, not under accelerometer control, then how is that different from simply having three separate cars with single-speed transmissions?
Bottom line: Don't assume it is a kit. Buy the cheapest servos, car, and radio components you can get. Work on the programming and remote control aspects. I second the single-speed car suggested by retched. After all, it is electric. Unless there are some very special applications, they don't need multi-speed transmissions.
Later on and from a development standpoint, you may want to consider a car with independent motors for power.
there are multiple header files in BTR folder provided, how can i make a binary file to download the firmware in microcontroller?
the instructions say
"The software is written in C using the MSPGCC (http://mspgcc.sourceforge.net/), a port of the GCC to the MSP platform. The JTAG debugger is from Olimex (MSP430-JTAG http://www.olimex.com) and is used to download the firmware into the MSP430.
The firmware comes with a makefile – unzip the sources to any directory and run make:"