edis 5 with pats means the wiring will be "difficult" to say the least
keep the car as it is until it goes wrong, if you had the eariler version you could do the swap no sweat

you can run the car on the earlier eec4 stuff but then you don't get the vriable inlet stuff going on, just try and piggy back that system onto the eec4 stuff

or

get a pats bypass set up from the states