Also keep in mind that those super-light cars have severely limited engines. i.e. lower compression and stock cam lift vs. 12:1 compression and 0.600" cam lift that everything else gets.

But yeah, it almost seems like STU is a run-what-you-brung-free-for-all with seemingly every car on the planet allowed to run in the class in some level of prep. I'm sure this is making it incredibly hard to police the class from a tech standpoint as well.

Welcome to New-Production, not Super Touring.