Just because it was mentioned several times now as a an advantage of 2wd:
Reducing the weight around 50grams won't do nothing in laptimes. And here you can believe me. You will have an advantage if you could reduce the weight around 150-200grams. That is the point where a 4wd tc will go faster in laptimes on tight tracks. A FF tc will react much faster to weight reduction than Rwd.
So in this 1/10 scale class and motors of 21.5t and stronger 2wd will have no advantage on tight to middle large tracks. On large flowing 1:5 tracks where traction is not the key to fast laptimes this may change.