EDC will give you 122 HP, however, the standard pump can be tuned, AFTER fitting a full width intercooler to give 145HP, which is quite an improvement - and is how mine is set up - IMHO it is very nice to drive, and driven like an old fart, it is economical too.
The 300's will actually produce towards 200 HP with extreme mods - BUT the head will melt in short order if it isn't treated with a lot of respect.... (IOW don't bother - ask me how I know
)
This guy's website is worth a nosy:-
http://jeremyjfearn.co.uk/
EDC was a good idea at the time, a half way house 'tween mechanical and common rail, with significantly increased injection pressures - BUT the serious problem now is that #4 injector, and its sensor is NLA - when the sensor coil fails, engine MIL light comes on, and you have an instant MOT fail
The system
was highly reliable, but the lack of availability of spares would stop me doing any conversion - I was forced to take EDC off my 300 Auto due to the failure of #4 injector coil - I was quoted £1K to make a new injector
if you were to change to EDC you'll need the pump, computer, a full set of injectors, the crank position sensor ( and the hole in the bell housing to accommodate it), and all the associated wiring, and diagnostics.