DGA has the idea. Granted, a lot of paperwork never gets looked at - we have really high power approved repair stations that routinely skip ADs on annual. One Mooney went for twenty years without fuel tank or control column AD compliance. Another doesn't do the Champ DMB wheel AD. And I mentioned the Cub muffler AD missed by three different shops (I insisted on an Atlee Dodge muffler - I hate doing that AD on a Super Cub).
So a fed says "minor" (by the way, modify a wing rib and it is not "minor"). Then change address and IA. On the minuscule chance that your new IA even spots it, you could be in for an expensive "un-modification!
I really like the less extreme wingtips, shown above. We do have a Super Cub here with those giant droops. Nobody likes them. Dakota makes reasonably good looking tips. I have no idea if modified tips do anything for a Cub. They usually hang them on after 200# of other kitschy mods, so performance is down from the get-go.
The statement by the fed was in reference to a cessna wing, with no modifications involved. Simply another shape at the tip. I do believe if you start cutting your Cub wing you will be doing something considered a major alteration and the requisite paperwork would need to be filed.
The comment about him calling it a "minor" was aimed at the idea of whether or not the particular shapes had much to do with adding performance.
Again, I don't know, and would love like the next person to find the magic bullet.. but it all seems to come down to weight.
A friend of mine commented that he wondered if the plane would slip as well without the original tips. That was food for thought for me and enough to decide to keep the nice round blend of original when I finally put mine together again.
Pure perfomance - my bet would be on the last rib covered with fabric.. but I really dunno and really don't care.. except for gaining knowledge.
One good reason to file a 337 is to have it for the time the "problem" FSDO guy shows up. Since there is no particular requirement to retain maintenance and minor alterations (other than transponder) records past a year, it's easy to have things not on the books. With a 337 you can show it was agreed to at a certain point in time. That's why I like to file them if I know they will be well-received by my PMI, because then it's on the record, whether needed or not.