Another long-time modification that I’ve never posted on is my SpoolinUp coil-on-pack. I’ve had this for as long as I can remember, I think on my black Evo, and I was a relatively early adopter of the part. It is a massive improvement over the stock system with excellent build quality, including Denso coil packs and a carbon fiber backing plate.
As mention, it’s been a long, long time since I adopted this part, but I remember experiencing immediate improvement in the overall smoothness of how the car drove. It provides better spark, improved idle, efficiency, acceleration, and throttle response, and still fits under the stock cover. Long delayed post about it, but I was doing some work on the valve cover and managed to snap a pic of it.