Not much myself, just the usual things.
sub 2:30? Ouch, sounds like your missing a major shortcut. Also, you know the part right after the two loop-da-loops with the sliding rock. You have to be quick in getting there before about 1:31-1:32, because then it pops back in and you wait to costing you precious time. Skipping the wall-running section....idk, i'll have to try that sometime.
Just a little tid-bit, to save about a sec. or a half of one(maybe more), when you go to use the shortcut(the one with the multiple boost pads that lets you skip a sharp curve with all the market stands), try to drift boost into it, then mash the RB button. You'll hit an extra boost pad, speeding you up, and hitting the earlier of the two other boost pads that direct you to the boxes with the QTE, saving some time. Confusing? Hope not, lol