I started with WASD's, complained about the pings for quite some time, theorised how and why they could be happening etc.
There are two topics:
1) Sound stage (case mods, plate)
2) Ping (springs)
Most people combine these two erroneously, make sound stage improvements to prevent the ping, which in my opinion is faulty
The WASD case is very hefty yet empty, that's why it doesn't have a good sound stage in my opinion, there are a lot of empty space to amplify the pings, I think that's why people associate pings with WASD's, otherwise all stock keyboards have it
The only solution to switch pings is to lube the springs
So just de-solder the keyboard when you get it, lube the switches, fill the case with whatever you can find and enjoy a great keyboard with an awesome sound stage (sponges and stuff)
I also recently re-considered WASD V2/Code's, as hasu's PS2_to_USB Teensy based converter is extremely simple to make, it upgrades WASD's to NKRO over USB and adds programmability, however, I skipped, the WASD cases gets too dirty with my usage since I tend to grab the keyboard from the sides
Anyway, long story short, you can't prevent the ping without de-soldering + lubing