There are many falsehoods about how stance 'structure' gives bodyweight behind a punch. I have even read long articles by some (shall remain nameless) wing chun 'masters' who rag on about how slight differences in 'stance' structure are what gives wing chun power. This type of talk is best to be ignored. In a real fight, you will not be in a rigid stance so claims that this is where wing chun gets power are totally ridiculous.
You can however rely on basic movements thatdo add bodyweight power. The 'falling step' is devastating if properly applyed. And full credit to this goes to boxer Jack Dempsy. Also, do not forget that you can turn your hip and torso into the punch. This adds reach as well as body weight and is found in the wooden dummy. Spine extension also adds power as does forward motion. Chainpunches delivered only using the arms as in SNT form are not maximul power as they do not utilise full body weight. However, advanced wing chun teaches the methods decribed to add to this basic line of attack.
FCF: So, who will you be facing at the next PRIDE event?
'It doesn't matter who the opponent is, I expect to win by knockout'
-Vanderlai Silva