From what I can tell if you look under the Exige mesh grills their clam has some paint and a bit of finishing. If you take off the Elise grills you'll see paint but the finishing isn't all that terrific because it's meant to be hidden by the louvers and the edges of the louvers.Can the louvres on top of the Elise front clam be replaced with the mesh that is found on an Exige? Only interested if this is a simple swap.
I think that's why you see EliseParts (and who knows who else) that sell mesh grills for the Elise that have the edging in tact to hide the unfinished stuff below (but still giving you mesh over the radiator).
Also, you can cut out the louver section and leave the edge frame with the stock bits from an Elise but it takes quite a bit of work.