on yeldar's test there was roughly a .2 second difference on barrel rolls
Leungbok said there is a .15-.30 difference depending on pitch up, down ect
karsten said there was a .4 difference for BR and a .2 for speed pads
Now, I would think that you hit more speed pads when you don't barrel roll, so it would seem that sometimes it would be faster to not barrel roll (if you were to have two speed pads you could hit maybe and not hit if you were to br)?
Also, what time difference does a straight boost give you? is it more or less than a barrel roll?
not counting shortcuts of course like chenghou reverse