I've had three Helios' and I stayed in the Plex input most times. From what I've read from the 50 watt owners, you have more sag. 100w will have more punch. Probably doesn't answer your question but I can't understand wanting a 50w when the 100w has the 30watt jmp switch which gives you that sag. Even Reinhold mentions that in the Helios video.