When I say K.A.R.R. was dumb & gullible in "Trust Doesn't Rust," I'm referring to things such as not recognizing obvious slang like the "slammer" (he could have figured this out from the context of the conversation) and the instance where he's trying to figure out the dynamics of a fast food place's speaker. Even Tony and Rev assumed KARR to be a fool by trying to trick him into getting what
they wanted. I don't think it was KARR's intelligence that made him necessarily get Tony and Rev to kidnap Bonnie, more like an instinct for survival due to his self-preservation programming, plus the fact that he directly asked them to do it rather than trick them.
In "K.I.T.T. Vs. K.A.R.R.," KARR uses metaphors such as the "genie in the magic lamp" to persuade John to be his driver, ultimately so that he can acquire his necessary parts. He also now seems to be more aware of life situations such as needing to earn decent money, and learns to use John's weaknesses to persuade him into getting his way. He scrambles Eddie's pacemaker to set up a situation where John would need money, as well as using the armored truck as a decoy to lure Michael & K.I.T.T. into a trap. KARR must have learned from TDR the concept of trust more deeply and learned from experience, thus now
he became the one to manipulate people to get what he needs. Though technically he did do it in a fair way; he scrambled the ATM for John to get him the $5,000 so that he would go on the "errand."
A true good vs. evil story; KARR can be compared to the Devil on one shoulder as in having the power to get someone anything they need, though in return they need to show their loyalty, just like the idea of selling your soul to acquire things you want in life. KITT can of course be the angel on the other shoulder.
