Quote from kut2k2:
There are things that can enhance your positive expectation, things like good money management
At the roulette, the casino has a 5.4% edge if you bet on the numbers (1 to 36 and 0 and 00) and no money management in the world can change that percentage.
Same thing with trading, you cannot change your edge with "good" money management, because "good" money management is ALREADY one of the components of your trading system.
In other words, for each trading system (assuming its rules are clearly defined), there is an OPTIMAL money management. Deviate from your optimal money management, for example bet more or less or change the value of the stop (or trailing stop) and you will degrade the performance of your trading system. In fact, your average profit per trade can even become negative, even if you have a winning trading system.
Quote from kut2k2:
and lower commissions.
Absolutely, lower commissions and/or spread can greatly enhance your average profit per trade while reducing the drawdown. It can even turn a losing system into a winning system in some cases.