There are a couple of people on here who have boosted K motors, a couple of examples:
Red Rocket's 5k Turbo Efi Ke55s
Jaydnisevil's 4k Turbo Ke70
Taz_Rx's 5kte Ke55
Just have trawl through the rides threads to see if you can find more.
Also,
, which is apparently this guy's old car. He's still active on YouTube so maybe he'd respond to a message if you have got questions.
Edit: Mute your speakers before you watch that video, trust me.