T.Pirate,
The 289 already has aluminum in the front and rear wheel wells. If you leave 'em alone, they will look original.
The underside of the of the original cars' fenders were painted black, I think. The street cars may have been undercoated to prevent "starring" from stones.
We usually undercoat the wheel side of the aluminum too, to quiet it down a bit. Driving over a sandy road sounds like a small cement mixer without it.
