Nitrous Dioxyde was the GM1 system. As far as I am aware, they tried the MW-50 quite early (A4 or something) and found, that the benefits were too small at least at that time of the war. The engine just didn't work that well with the MW-50. I don't know, if there were large numbers of Antons with the system, but I doubt it, after all I read about it.