I just received the kit today and put it together. I've had my 60HE in a Holy60 for a few weeks with the stock PC plate, foam and Jade Pros before picking up this kit.
First, I love the envelope it all comes package in, and everything I needed was inside.
Now, while there is a nice video to follow to get the general idea of what to do, you may or may not have to do some cutting/tweaking to get it to work for your setup.
For me, I had to some cuts to the PET film, PE switch foam, and the plate foam to get them all fitting properly around my screw-in stabs which are not the stock Wooting ones but rather Typeplus stabs.
I'd say the only real challenge I had was getting the FR4 plate seated properly around all the stabs as it's a very snug fit, and I'm so used to the pliability of the PC plate that having something less forgiving like the FR4 plate made that part a little more difficult.
Once that is all said and done, this is a great package. The FR4 plate, along with the additional foams and film have given me a clean, poppier sound when typing and I love it. Listening to audio of the FR4 plate vs the stock PC plate is very surprising. The sound with the PC plate is while a touch lower in frequency, also sounds muddier vs the FR4 plate.
I can absolutely recommend this kit, especially if you're going to be putting this in any compatible case like the Tofu Redux, Holy60. You might as well go all the way and extract the most sound you can out of this thing.
Also, I thought I'd talk about the PE Switch Foam quickly as the site does mention it can affect performance. I'll say that for anyone that uses the full range of the switch may want to be mindful about using the switch foam. For instance, if you use dynamic keystroke, there is a chance that the final bit of travel gets affect by the foam. So if you're someone that uses DKS, or like to have long travel distances for their actuation, you'll want to forgo the switch foam.
For anything else with short actuation, it's perfectly fine, and you'll love the marbly sound you get out of it. Seriously, this combo'd with Jade Pros is amazing. Fantastic sound for an HE keyboard.