I used to take 125 mg quite frequently before my workouts along with several cups of coffee. With what they know about this stuff these days though, I would not advise taking more than 50 mg at one time. In fact I wouldn't take it at all and I haven't for several years.
Any amount of ephedrine makes me feel like shit. It reminds me of when I used to take dexedrine and ritalin a long time ago, makes me feel like Im comin down of of them. One of the worst feelings. General bitchiness. T-rex is way better.