I used to do some sub-sub work for them while I was living in so. Cal, They frown on it, since it's what gives them recognition from other 'surf' brands. Bottom line, I wouldn't, unless the alteration was radically different. Hell, I got a tat with a wave that 'kinda' looks like it, (just part of the work) and was 'jokingly' told about how it 'could' be construed as copyright infringement...