When I was testing the kit I noticed the smoother idle right away. HID warm up is faster as well, along with smoother highway driving at a maintained speed (Wasn't sure why, but smooth enough that the GF noticed).
Looks like everyone here has covered the bases... XWEK = -X- Wire Enhancement Kit
If you think everyone is experiencing a placebo, note that I also pulled measurements before and after the installation of mine and it significantly reduced the resistance. Went from 1.6ohms down to .4ohms of resistance. Our electrical system barely pases the grade and this product is the fastest and easiest way to solution the problem. For the money, it's somewhat of a no brainer in my opinion. The thing could be made yourself if you have the knowledge set and access to the tools and supplies but I would presume you wouldn't even save that much money going that route.
Lastly, and the part that I personally like a lot about the product is that the installation is super clean. It allows for a nearly OEM look and doesn't obstruct anything or require any goofy splicing or cutting. If you check out my build thread, there are a number of photo's of my engine bay and you cannot even see it in there (which I love)
If someone wanted to buy a quality crimper (not the cheap hammer style that has no quality control) and all of the components to make a 1 off of something like this they would definitely be paying more than just purchasing one of these kits.
It is now almost a game with build threads to see if you can spot an XWEK in the bay.
While I'm convinced the upgrade is worthwhile, I've had a surprising number of problems with those plastic AGU fuse holders in my engine bay. I've had several get brittle and crack, or develop dodgy connections at the set screws. Maybe a brand quality thing.
Could be a combination of things in my case. Might have been some extreme cold, lack of slack on the cables, or overtightening. Might have been the cheapest sort of Chinese-made crap. Still leaves a bad taste in my mouth whenever I see those holders.
What rating are you using on that fuse? Maybe I could swap in an ANL block to satisfy my paranoia.
Thanks. Certainly doable, and I'd feel better if the threaded polycarbonate shell wasn't structurally holding the circuit together. (Dead short to ground with 4 gauge cable was rather alarming). I did up my own charging and ground cable improvement on my Chev Cavalier (which the community was calling the "Big 3" upgrade) some years ago, but it certainly wasn't clean, measured, and properly crimped as the XWEK.
Speaking of the fuse enclosure, be careful when routing it under things. Mine came apart and I had to reattach the wire (sans shroud) after backing the screw out to allow reinsertion. Take a screwdriver and snug it down on each side before installing.