Rear 930 rear bumper extension question

[Yan2947]

Any idea what 930 type these rear extensions are from? They are fiberglass. Should the vents have any covers or louvers? The car is a slant nose conversion from the 80's.

thanks!

[TRE Cup]

If you want to keep the rear extensions clean, block those off. They serve no performance advantages over original. A simple piece of black plastic glued on the wheel side of the opening will take care of it