An absence of modding tools hardly means an absence of mods—just look at GTAIV, and the impressive modifications that have cropped up since the game's release. An SDK would obviously help the process along though, which is why it's wonderful to see the efforts over at the Saints Row Mods forum being given Volition's official blessing. The first stage of Saints Row IV's newly released modding tools allows players to make their own weapons, though you're going to have to up your game if you hope to compete with the likes of the dubstep gun.
A guide on how to use the modding tools is located here , and while they don't turn the process into something a simpleton (i.e. me) could easily follow, I'd imagine they make it quicker and easier to replace existing content without having to get stuck into the source code. Later releases of the SDK will allow for easier modding of other parts of the game, but weapons seems like a good start.
If you're wondering what the above image refers to, Volition have given modders access to a weapon skin from the recently announced Gat out of Hell , although it's lacking the behaviour/characteristics here that will be featured when the gun is available for wielding in GooH itself. In addition, a file featuring all of the weapons from Saints Row 3 and 4 is available to download at this link .