I did not realise until yesterday that the Nissan ECU controls the boost electronically. Therefore if you are getting remapped it makes more sense to fit a daughterboard that makes the ECU fully programmable, i.e. a nistune. It can then control the stock actuator.
I found this out as I was looking last night on the website of the tuner who fitted a nistune and remapped my primera (SR20 N/A), the video showed a black S14a, the text said it was completely stock apart from a cat-back. first run 174bhp, achieving 0.4bar, text said due to 'a tired actuator' (can't say if this makes sense) - he bumped it up to 0.7 bar via the ECu and remapped it, got to 230bhp. Not bad entirely via the ECU!
Anyway there are several nistune installers in the Uk and I think there are also alternatives to nistune. ( I am not affiliated to them just passing on this info). I woudl guess its more economical than seprately getting an EBC and modifying the ecu.