Ty - No problem.
I ran the heatsink for the first time last sunday. It doesnt cover the whole vent hole. If you place it just right, it covers about 1/4 of each vent. I also run stock.
My only dislikes of the heatsink are thats it's blue ( no biggie ) and that it moves the motor out very slightly... Maybe not enough to notice, but it does move it out slightly...