I've touched on Dread Guristas modules vs Caldari Navy modules stats and prices before here but it needs revisiting.
Most Caldari Navy modules have Dread Guristas equivalents with exactly the same stats, skill requirements and fitting requirements. Other than the names they are identical but the Dread Guristas versions are usually much cheaper.
I've checked more than a dozen CN mods vs the DG versions. All of the ones I checked had identical stats and requirements. Missile launchers (all of them), shield boosters, shield boost amps, etc. I didn't find any that were not identical. I assume the ones I haven't checked yet are identical too.
Caldari Navy modules are purchased from faction stores with Loyalty Points while Dread Guristas modules are drops. Generally speaking the CN versions are available in somewhat greater numbers but there are nearly always plenty of lower priced DG mods up for sale too, especially at the main market hubs.
As far as I'm concerned, DG/CN modules are the same modules and as such should sell for roughly the same amount. If anything the CN version should be a bit cheaper due to being in somewhat greater supply. Yet the cheap DG version sits there piling up at the market hubs and not selling very well, while the (usually) far more expensive CN version not only sells quicker but in greater volume too.
Being a trader this drives me nuts!
I've had CN X-Large Shield Boosters sell for over 200 million each (they're usually 120-150 mil) within hours of posting. Buy orders for them are often over 100 million and rarely much lower. Yet it can take weeks to sell even just one DG X-Large Shield Booster (with the exact same stats) for 60 million on the same station. The same is true for other CN / DG module pairs too, the CN version is usually priced 2-3 times higher yet sells faster. For missile launchers DG are often around 1/2 the price of the CN equivalent. I've seen DG shield boosters and boost amps at 1/3 the price of CN.
This can only be due to players either not knowing DG and CN modules are identical or not bothering to check the price of DG mods before buying CN mods. Otherwise it'd be a no-brainer, everyone would buy the cheaper DG version until stock runs out or the price rises to the level of the CN version.
There is a technique that sometimes works to sell DG modules for more. When the price of a particular DG mod is high, I'll post one for quite a bit more than it usually goes for but still significantly lower than the CN version is currently priced at. Then I'll ask in local chat why the DG mod is so much cheaper when the stats are identical (linking both versions of course to make comparison easy for potential buyers). When it works someone buys a DG mod (or several) within minutes. It's win/win, I get a higher price than usual and the buyer pays less than he would have for the CN version.
I've also noticed the same phenomenon with a single item across a couple other factions. That has me wondering if other modules for those 2 factions are identical too. In fact I'm wondering if there might be several pairs of factions with identical mods. I haven't done any research on that yet but it's definitely something I want to look into eventually.
Hopefully this article will help some players find better deals and save some ISK. Maybe if enough players start checking DG prices vs CN prices it'll help equalize prices too.
Oh yeah, Caldari Navy Torpedo Launchers are for dummies. I leave it to you to figure out why. :)