Yes, I am still planning to implement a preview of gun's stats, but there are some complications. When you add an "Exp" modifier, you're essentially giving the bullet a gun, that it will fire when it dies. This allows the player to change the behaviour of this explosion, by for example, adding a "Ho" modifier, which will make shrapnel home onto enemies.
Whereas "Spi" makes your original bullet invisible and "untouchable", while creating a new bullet, that spins around the original one. Guns and bullet are stored in two separate and I have no idea how to track which bullet belongs to which gun... Although, now that I think of it, every gun has a bullet template inside of it, but on the other hand while building a gun from modifiers, I don't store guns, I only store their properties... Anyway, I don't know how to implement it yet.
Also, it will involve changing the UI and I hate the UI.