RE: is it really worth it?
There is absolutly no kind of comparison between those 2 cars. The 4tec is a rtr car with near 0 handeling no matter what you do to it. is only good for dragracing and will hit 70.
The 720 is a race car, has excellent handeling and depending on the motor and gearing you choose, will definatly hit 70mph and will get there quicker.
The price difference between the two is definatly worth it andthe 4tec isnt worth the money even tho its about 325