Guess what I found?

A scrapped Degreaser attribute! :aaaaa:

Charging... Poor bots don't even realize I'm there.

See ya, suckers!

Oh, what's that? You trying to get revenge for your friends?

:byewhore:
This is more fun than I can even describe. Unfortunately I can see how it's broken as fuck without some major cons. It seems Valve was also toying with attributes alongside it related to extending/shortening the flame's width and length. There's no current visual representation of those in the game, so while I was trying those out the flame looked the same but the physical effect was there. Extending my flame to 500% length was pretty fun. 
My hat goes off to you sir. Most Emporium projects i've seen are usually just visual and cosmetic projects, whereas you've been toying around with gameplay and functionality, which is pretty much the meat of any game.
Though your set's disadvantage could easily be circumvented via the Eternal Reward, having the default Knife required for the set to be complete is nothing less than a stroke of genius. Although if you could try a bit of Sourcery, why not try and make it so that instead of requiring the Knife to complete the set, having the Eternal Reward equipped will function as a "set-breaker", thus meaning that even with the Ambassador, Dead Ringer and Frenchman's Beret equipped, the set's bonus is nullified if you carry the Eternal Reward, thus meaning that if a different Knife unlock becomes available in the future, you can equip said New Knife and not be required to carry the basic Knife in order to complete the set.
I know it sounds very complex, but is it feasible?
Also, I know there's no way this could be used as a clientside mod, but if it were implemented via Valve's doing, or as a server mod, it'd probably count as being implemented.
Unfortunately, there's no currently implemented method of excluding certain items from the set's effect. I would like to include the regular knife into it, but as of now there are two knives in the game: the default grey one and the yellow renameable ones. I'd have to exclude one of those two in order to have it in the set. It was just an experiment set anyway; I was just making use of unused attributes and seeing how they worked. v
v I've since reduced the disguise time addition to 2 seconds, by the way. Having four seconds added on to the disguise time is extremely difficult to deal with. And I've also found that Your Eternal Reward actually makes the set more difficult; being forced to use it with the Dead Ringer without the silent uncloak is a pretty big setback.
I did find, however, that I guess I can include one item into multiple sets. The item won't list the extra sets in its attributes, but the set itself will list the item as a requirement. Interesting.