It gets really hard after 20 stars. For akina, i lose to bunta
consistently by less than 5m. I am right behind him all the way but
dont seem to be able to overtake him. 
As for irrou, 25 stars and above, bunta will shoot off at the start
and you can only overtake him near checkpoint 1 and beyond. If you
overtake him towards the last stretch of the road, you will still
lose as he will overtake you during the straights before the finish
line.
Gets tough.
