To install the VX motor you will need to rewire the o2 sensor to a five-wire, run a wire to the ECU for vtec, and wire-up the EGR control box.
Other than that, it is straight forward. If you can't install the swap yourself, it would probably take a very long time to recoup the cost of paying someone to install it and in that case, just stick with the CX motor.
The transmissions/clutches/exhausts are the same between the motors, so you could sell those parts off of the VX swap in order to fund the swap.
On the never-ending quest for better gas mileage...