[Walt Fricke]

I'm pretty sure you already have them. The older covers were almost flat, with just slightly raised ribs. The "Turbo" covers have ribs maybe 19mm tall in an egg crate lattice pattern.

Porsche only lists the Turbo style covers nowadays for cars with the 11 bolt exhaust covers through '89 anyway. The 2.7s had the older, unribbed, style when new. So one parts catalog doesn't help here. The 2006 PET says you have the turbo covers, but that again could be because Porsche most likely discontinued the older covers when they equipped all the cars with them from the get go, as there was no reason to have an inferior cover in stock.

If anyone wants the older cover, I've got a pair I'd part with most modestly. But, other than concours types, I can't imagine why anyone would want these. Retrofitting for authenticity?