Changing of a MODs primary stat

Here's a thread on gaining and developing mods: 

Modding: Quality, Farming Efficiency & the Cull | EA Forums - 13162736

For your current problem, what you need to know is that you're going about this the wrong way. 

By far the best place to "farm" mods is in the Mod Store in shipments. Most mods are trashed soon after you get them bc they aren't what you want, but you often spend many credits finding out that a mod is not what you want. 

Many people refuse to buy mods in the Mod Store for credits bc you can get mods "for free" from challenges. 

This... isn't accurate. Golds in the mod challenges are very rare. Golds in the store are very common. While you'll pay 3.9M credits for a gold in the store, when you use the challenges, the number of mods you end up levelling to 3, 6, 9, or even 12 before you decide to trash them is huge. You spend fewer credits per mod, but you spend just as much for each mod that you actually keep. 

Meanwhile, the mod challenges that spit out worthless mod after worthless mod cost 50 crystals for another 120 energy to gain 7 to 8 more mods. 

But refreshing the mod store is 15 crystals and there are more than 8 mods per refresh. They're also of much higher quality, and you can see the Set Bonus, Primary, and some of the secondaries before you buy. 

Moreover, the mod store refresh cost doesn't appear to change. There's a limit to the amount of mod energy you can buy per day before the costs go through the roof. But not so for mod store refreshes. I admit i've never refreshed 100 times in a row. I think the most I do in any 6 hour period is usually 10-15 when I'm focussed on farming, and I think my record is still less than 25 refreshes in one period. So maybe there's a limit when they start charging more per store refresh, but if there is, I haven't hit it. 

Meanwhile, if you're using your energy for mod challenges, you can't farm mod slicing materials, which puts you behind there. That's bad. 

I do recognize that with the mod store you can't control the set bonus, but there are only so many set bonuses, you can keep track of what you need, and unlike the challenges where you might have to pay to find out if a mod has speed, in the store you can choose to only buy mods with a good constellation of secondaries -- including speed. 

Stop using the mod challenges and do yourself right: mod energy for slicing mats, and all those crystals that you used to use for mod energy refreshes go right to mod store refreshes.