I loved the idea of SPM, though not necessarily the way it looked. To me, K.I.T.T. looked plain weird will all those extensions. However, when K.I.T.T. went into SPM, that was frequently the climax of the episode in my opinion, or at least for me it was. I loved the idea of K.I.T.T. charging up with all kinds of things popping out, the sound of a high-tech device charging up, then rocketing to 260+MPH.
I especially thought it was cool the rare times K.I.T.T. went into SPM at night and every extension was underlit with red lights. In terms of appearance, that, on the other hand, I did like. Reminds me of the ground effects on the cars in The Fast and the Furious. A great thrill for a child watching the show like I was and playing along with my Knight 2000 Voice Car! Ah, memories.