Basically this blog has absolutely no purpose other than showing people just how tiny changes in weapon parts and names in the weapon generation engine in Borderlands can change a decent weapon into an awesome one. Using the Combustion Hellfire as an example (since in my experience it has the most variance in stats based on parts), we'll look at a simple mag swap, a prefix addition, and a completely different prefix pulled from a different weapon name pool.
Now, keeping all the best standard SMG parts, let's switch to the "unique" Thumper mag.
BIG jump in damage, but also a big hit to ROF. The Thumper mag trades in ROF for higher damage. The SMG is now more powerful, but it's no longer a RATATATATA machine.
Now if you'll notice I've left "Autoname" checked. This is to keep weapons "legit", i.e. they are actually possible combinations that the Borderlands weapon engine will generate. Now, I'm gonna try and squeeze a little more performance out of the first variant of the Hellfire, the one with the standard mag, by changing it to a non-legit weapon type with a different prefix (since Combustion is technically the only legitimate prefix for the Hellfire).
The first image is from the available SMG prefixes. The second image I pulled from the Support Machine Gun prefix pool.
And here's the really interesting one. I pulled the highest quality multiplier prefix from the standard SMG pool, and one from the Shared Prefix pool.
You'll notice that the rarity has actually turned from Legendary to Rare. This is because the only thing that give the Hellfire it's legendary status is it's name. Now, let's make it pearlescent (the highest level of rarity).
See? Tiny tiny variations in even the weapon name can completely change a weapon in the Borderlands engine.