Just raise the battery voltage, decrease the resistance of the controller shunt or do both. The latter is what most choose. No idea what's different across the firmwares, I have never seen a change log? They should be releasing a 1300W variant of the M620 soon so that might be worth trying to...
Have you tested this? I have a suspicion it might not be a good idea. I am genuinely interested to see what happens. With the upgraded controller it may deal with temperature monitoring and rollback much better than the stock controller. What does it do as the temperature increases? I wouldn't...
Even fully compressed it looks large? I know absolutely nothing about suspension at this time (I just ride on tarmac) but mine went right in. It's a bit off topic but I once had a DNM shock like yours and it felt more responsive than my Rock Shox deluxe select+. I have only ever tried 2...
I genuinely didn't know the way it went together until I fitted it to the fork. Once I assembled it it was immediately obvious.
Have you done much more with your E55? I think the last time we spoke on FB I had just started my E56. I am not sure why the E55/E56 platform isn't more popular tbh...