Please strongly consider modifying a fiberglass decklid instead of a nearly irreplaceable steel decklid.
instead of just cutting notches for the stacks, a much cleaner look can be accomplished by trimming the entire edge a sufficient amount to clear the stacks.
The first time I saw this, I was scratching my head, wondering how he had managed to move the engine that far forward until I realized the stealth manner he had clearanced the decklid.
if you do cut the steel decklid, save the removed pieces in a clearly labeled and identified bag or box and do your best to see they are kept with the car for a future owner
Larry