EFI is where its at for throttle responce and easy starting.
It is also a bit more easy to get good low end torque with EFI given the proper parts.
You could get a TPI unit and do a EFI yourself or just get the ram jet and be done.
Given the choice I would go for the ram jet.
Keep in mind that you will need to run a return line back to the tank and use either a inline pump for EFI ( about 100$) or put a pump in the tank.
Thats pretty easy if you can get a tank out of a newer vehicle and put it between the frame rails.
The inline pump can be got for about 100 at
http://www.jimsperformance.com/carti.html