I've been developing some systems for a while and looking at Collective2, I see some interesting ones I could compare to. But how interesting are they really? Namely, I can't seem to find answers to some key questions that determine how accurate the hypothetical results of various systems really are. I've sent e-mails to their customer service, but no reply. Maybe someone here can enlighten me on these questions: 1-Once a system is introduced to C2, it starts generating data for a portfolio which then shows up in the hypothetical results charts. Can a system be changed (recoded/improved) after introduction and if yes, what changes are allowed to be made? 2-Can the system admins turn the system on/off so that it stops generating signals and thus creating a "flat line" on the chart? 3-Can system admins cancel signals manually (since i've seen some signals cancelled) or do the systems do it automatically and there is no other way? 4-Some hypothetical results charts look like they are going up, but then they have a few downward spikes. I'm not sure what they mean. When I looked very carefully at the "Recently closed trades" table there were no negative trades reported at those times. Could it be the trades were open for a longer period and thus visible on the chart, and in the meantime the PnL of the portfolio was hurt by the underlying oscilations? These are fairly important questions for me and my research right now so any answers would be appreciated. The C2 forums seem to not generate much activity so I thought I'd ask here. Thanks.