[Beaver]

Okay, the EGT not being static, but rather increasing along with intake air temp gives me more to chew on. And the Firefly charts are most helpful; they would probably apply almost directly to my Metro. Basically what I read then, is that I can leave the air horn running out through the front bulkhead, as is the stock configuration, and it won't help or hurt my mpg, though it may give me more hp at wot. Right? It may lower my egt and combustion chamber temps however, perhaps allowing me to run slightly more timing advance or use a lower grade of gas.

I can't thank you guys enough for your thoughtful and informed input! And I like the idea of not doing anything at all; inertia is my specialty. I just love to leave well enough alone every chance I get.
Cheers!