Ok, jury is in. I got a package from Sprue Brothers today with 4 Eduard 109Es (at 12.49 USD a pop, how could I get just 1?) I got 3 of the mentioned E-7 Trop kits (84167) and for good measure, an E-4 (84166) to compare. And the results are in. Drum roll please...
After comparing the two kits, it is obvious that they are in fact the same exact sprues. Case closed. Although if you have the choice between the two, get the E-7 trop, as it comes with 2 decal options (with full stencils!) and some nifty "super fabric" seat belts.
As for the whole 4mm too long deal, I'll let you be the judge. From what I have read, the Airfix kit is pretty spot on 2 seperate scale drawings (not my actual research, just what I have read, so take with a grain of salt) so I decided to see how the Eduard measured up to the Airfix. As you can see, it certainly is longer. L= Eduard R= Airfix