I have had almost all Proac speakers over the years - seriously! I still have pairs of 2.5 d38 d 3.8 d80 and d100. If you like the Proac "sound" the differences between speakers are there (obviously as otherwise there would be no point) but improvements are progressive as you move up the price chain (as you would expect), apart from the 2.5 which is a stand out "go for" quality wise and price wise. So my own conclusion that works for me is that you spend as much as you can and work at that model at your price point. You should be happy regardless
