If you're going to go with a calum ECU, either realtime or basic, don't waste the extram money on a g20 ECU. Those are generally worth more due to the no speed limit, and whatnot. Just get a 95~97 SE-R ECU, and send it off to him.
And as stated above, fuel atomization is better at 4bar, than at 3bar, and it's free power, so why not do it? Obviously you're going to want a FPR and gauge anyway, to fine tune your fuel pressure from a higher volume pump, so just up the injector rating and call it a day.
The reason I personally would choose a turbo timer, is because I run the car at the track doing test and tunes, and heads up track runs. I have a habit of jumping out of the car and turning it off when I get back to the staging pits, and that's not always good after doing a few hard pulls. Turbo timer is just piece of mind, tbh.