When I queried the whole injector thing when this car went BPU (in case anyone didn't know, it used to be mine), most replies I got seemed to be of the opinion that the stock injectors were capable enough of sustaining 1.1 to 1.2 bar, which is what the car used to boost to on WOT. I don't know why it's boosting higher now. (It used to hit 1.1 bar with the Nur Spec R baffle in place, and 1.2 bar without.)
I agree you'd need bigger injectors if you plan to continue to boost to 1.4 bar, but they are only stage 1 hybrids and I was advised not to go higher than 1.2 (aside from all the other mods that would have been required to support it). If you plan to rebuild the engine and leave everything else alone, I'm not totally convinced bigger injectors are required. Perhaps a smaller restrictor ring and an electronic boost controller would be more suitable? (The Nur Spec is a good free flowing exhaust, so I don't imagine EGTs would be too high if you keep the boost to 1.2 or below.)
(In addition to the bigger injectors, as already stated, you'd need fuel management and a map if you continue to run the car at 1.4 bar, otherwise you'll be back to square one in no time.)
P.S. In response to the air con issue... It certainly used to work, and you may remember I demonstated it to you during the test drive!!