curve fit is when you backtest a system and optimize it excessiviely, you can usually come up a set of parameters that looks great in the past, but will unlikely work in the future. You do trade with them, but clearly their trading is based on 3 specific rules and 5 specific filters, which obviously could be written into TradeStation or whatnot and backtested or automated, so I'm not sure what extra value trading with them would really add, since they really stress how straightforward rule based it is. Hence, I suppose it is really a $5,000 system you are buying, in which case I'd sure like to at least see their entire track record for.