Okay, so this is just to run a bigger wire so it can carry more amps, thus the excite wire will not be limiting the amount of amps going to the the solenoid. So the stock wire just isn't big enough. Alright that makes sense now. Thanks for the replies.

That should not be needed. Something is wrong. Either your batt cable is not heavy enough or you are getting defective parts. check the cables and grounds and make sure you have matched strong batts. Min 800 cca each.

My batteries are 700 cca, but not enough power shouldn't blow the solenoids, too much sound more likely to blow the solenoid. The batteries are newer Ac Delco ones that are matched, I think they're an exact match to the ones in my dad's 04 Duramax. But do the 800 cca do a world of difference in cold weather starting? I don't want to spend 250 bucks on batteries when mine seem to do get the job done. The only time I experience slow cranking is when the weather is maybe below 5F.