"To win the Sun Sigil, you'll have to complete the race in under 0 seconds. Imagine you reach the finish line in 35.9 seconds, having touched a bird. This would make your total time 38.9 seconds. However if you also touch 13 balloons, 13 x 3 seconds will be deducted from your result. So, the final time is below 0 seconds. This is a tricky challenge but not impossible, and you may need a bit of luck when it comes to how the balloons are distributed."

So..I'm not sure cos I never actually did it, but by this which was in the strategy guide I think it has to be *under* 0 seconds and not just 0? Ahh, I wouldn't even try it, too hard xD