Looking at the "Corvette" on the valve covers made me think I wanted something a little different.  The car isn't a Corvette and the wording needed to go.  Still, the fuel rail covers are nice, simple and easily removed.  With a little work, I was able to modify them using .125 aluminum, chamfered on the sides and painted epoxy black.  After cutting the aluminum to match the size of the impression in the covers (16.25"x1.5") I decided to use the logos that came with the kit.  I will likely have custom logos done for the exterior later.  The lettering was a bit of a pain to space properly.  I had to take some time to measure and mark each letter location.  I made the marks on a piece of tape running in a straight line at the bottom of the letters.  Once I had the letters in the correct place, I made a mark in line with each leg or tangent with the beginning of the curves. Using the marks as a reference, I peeled the backing from the letters and applied them.  The "GTM" logo is exactly 1.5" so it appears that there's a slight overhang.  I will accept this for now but if I was to do this again, I'd likely not chamfer the edges as much.  I could also flip the plates over and they would fit the impression better and be near-flush with the plastic surface, allowing a full 1.5 cross section for the GTM badge.

The covers or blank off plates are countersunk and screwed to the plastic.  There is no thread protrusion on the back side.  Threads are flush with the nuts and have red Loctite applied to prevent any fretting or wire damage from vibration.  Depending on how the lettering holds up to the heat, this may be good to go.  If not, I'll unscrew the plates, peel the logos off and apply metal logos.