Allright, my 600Ω Systems have arrived and are put into action. My short impressions from NoXter's exemplar last week are confirmed, already out-of-the-box they reach almost Gradessandro level in the speed section compared to the stock 250Ω suckers. I really love that increased blackness!
In respect of the sheer tone, I sense some more warmth and a bit friendlier highs (nothing spectacular though), and the bass balance is a bit shifted away from the deep bass towards the kick bass. Guess the deep bass needs a bit time to come out completely.