pre-workout stims are not as beneficial as you may think.
The amped up feeling may allow you to train harder than you could naturally, however this can lead to over-training. So in the long run, you are breaking yourself down too much and exceeding your recovery ability.
When I use pre-workout stims, I'm extremely explosive, however I feel very run down the next day and overall my workouts seem like rollercoasters. This may be good if you feel like you are just not movitated to get off you butt for a day or something, but relying on it for every workout is terrible.
So, using stims regularly/every workout will mess up you muscle building routine and it will no longer be as linear. You body is tired for a reason, using a stim to fight it is going to drive you adrenals down the drain, which is going to lead to CNS fatigue, and ultimately fat gains/muscle building wall.