I currently have 3 Strats that I Installed it in and have done a few others. Believe it or not, the PCB has fit under the pots with no modification to the guitar route on all of them, including MIA, MIJ, a MIC Squier CV and a partscaster. The only thing needed to make it fit is to clip one corner off the PCB with a wire cutter, or any other reasonable means to cut it. It's not that big in real life.
The kit comes with a replacement volume pot (50k active vs 250k stock) and the dual TBX tone control pot and parts which I toss in a drawer.
The install is relatively easy. The output from the pickup selector goes to the PCB, then a wire from the PCB goes to the new 50k volume pot, and two more go to a 250k linear pot that acts as a blend pot between the two (one is the boosted clean signal and the other is the boosted mids). T
The third pot is your tone control. You can do whatever you want with it, including install the TBX, keep it as a standard master tone, etc. What I usually do is use a no load 250k pot as a master tone. With it out of the loop on 10 you get the classic super bright bridge position and you can also brighten the other positions, or turn it down, and you have master tone on all.
The other piece of the kit and wiring is a stereo output jack for power. I have used this, but keep in mind you won't be able to use and TRS cables or wireless units that use a TRS for charging. You could also wire it with a normal output jack and a switch.
If
@DrewJD82 or anyone else needs help with how to install or wire one of these up, let me know. I am happy to help and I can take pictures of how it fits the next time I change strings on one.