The finish really should not matter. As stated before, as long as they are all the same heat range and resistance, you will have even power in all cylinders. The end of them all turns brown in the cylinder anyway

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Streetside: 1987 Mercedes 300E Petrol Blue/Green
2014 Ford Mustang Grabber Blue
1999 Ford Ranger Green

Dockside: 1968 Eltro 17
1985 Silverton 34C