Yeah and they change gears really quick so maybe that has somthing to do with it?

World Rally Cars run a lot higher boost then 30psi, they run the higher boost to take as much advantage as possible of the Air restriction so the higher the boost the more suction power.

That noise you here is the Wastegate with a small combination of turbo flutter, because there running such high boost and the gear changes are nearly instant the short high pitched chirp is all you get during the gear change to when the anti lag engages.