About a dozen years ago I had some clients with an insert. They didn't like the HUGE sheetmetal surround (I've never quite understood why they need to be as large as they are?)
They wanted me to build something "less." Since my "creative" side -- such as it is -- tends toward an industrial feel, I suggested stainless SHCSs in a counterbore. The screws do absolutely nothing functional, they just sit in pipe I tapped. I used steel channel.
Before:
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After:
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I actually took the stock surround and mapped out the slots which slide down on screws, then machined those into the channel, thus it anchors exactly as stock:
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