First off, great debate, guys, and sorry for the long post ahead...
Looking at both points of view objectively, it seems to me that the rule established in the
Knight Rider Bible of "How fast do you want K.I.T.T. to go?" might not necessarily mean it's established canon. K.I.T.T.'s Seasons 3 & 4 dashboard says his top speed is 300 M.P.H. Now, of course it has to have
some top speed on there because otherwise the speedometer's meter would have to say "As fast as you want" instead of "300" for its limit.
Now, judging from the fact that the highest speed we've seen K.I.T.T.'s speedometer go to (300 M.P.H.) is also the highest limit that his own dashboard says, I will have to conclude that K.I.T.T. does indeed have a top speed and that it is indeed 300 M.P.H. If anyone were able to post a screen shot of K.I.T.T.'s speedometer simply saying as much as "
301 M.P.H.," it would prove beyond the shadow of a doubt that K.I.T.T.'s actual speed can exceed the speed stated on his dashboard, and in that event I would be in full agreement with Victor because it would be breaking the limit to a point where the dashboard can no longer accurately record it.
In regards to Bonnie's statement about the 40 percent speed increase, I don't believe we can take it literally. If I'm not mistaken, her exact words were: "I think we can get a 40 percent speed increase." The key word here is
think. She made this estimation before Super Pursuit Mode was fully implemented into K.I.T.T.'s systems, so not only was it an inaccurate estimation, but it wasn't even installed yet. As stated earlier, a 40 percent speed increase from 200 M.P.H. would've put K.I.T.T.'s top speed at 280 M.P.H. which was undoubtedly proven by Matthew's screen shot to be incorrect if that were the case.
Furthermore, it's my opinion that the final speed increase once SPM was installed was actually 40+ percent above K.I.T.T.'s top speed in Normal Mode, which would be approximately 200 M.P.H. (which I'm basing off of K.I.T.T.'s Seasons 1 & 2 dashboard). Now, if we're going to take the
Knight Rider Bible's rules literally, I believe it would apply to K.I.T.T.'s top speed in
NORMAL MODE,
not SPM.
The Bible was written before SPM was even conceived by any of the writers, so would it then be fair to presume that since the previously established rules of the Molecular Bonded Shell made no sense once K.I.T.T. splits apart in SPM, can we also say the same regarding K.I.T.T.'s top speed? In other words, is it possible that the Bible's rules ended up being broken and thus irrelevant by the time Season 4 came around?
One more variable to take into consideration is the 100 M.P.H. increase when K.I.T.T.'s dashboard was upgraded in Season 3's "Knight Of the Drones." To me, that meant that K.I.T.T.'s top speed in Season 3 could also indeed exceed the 200 M.P.H. mark and that he was
potentially capable of reaching 300 M.P.H., but not
actually capable unless there were other abnormal circumstances such as the ramjet used in "Goliath" (does that make sense?). K.I.T.T. reached the 310 M.P.H. top speed in "Goliath" even though his speedometer only read up to 200 M.P.H., so it would obviously just show a maxed out 200 M.P.H. speed. Bonnie's Season 3 upgrade in my opinion would simply be for the purpose of giving Michael a more accurate speed reading by accomodating an extra 100 M.P.H. (since it was proven that K.I.T.T. did exceed 200 M.P.H. in "Goliath"), and I agree with Victor with his speculation that it was done to simply "plan ahead."
However, if Bonnie planned ahead in Season 3, and K.I.T.T.'s speed with the 40 percent increase could indeed make him reach 420 M.P.H., why wouldn't Bonnie have added another 120 M.P.H. increase on K.I.T.T.'s speedometer when she knew she was installing SPM and it would be making K.I.T.T.'s top speed even faster than 300 M.P.H.? To me that's even more reason to back up my point of view that he had a top speed of 300 M.P.H. and even in SPM I would imagine K.I.T.T. would only be capable of achieving that on a straight path with no obstacles.
Oh, and by the way, Season 4's opening credit sequence only show's K.I.T.T.'s top speed at 298 M.P.H. which still does not break the 300 M.P.H. mark. But even if it did, I don't believe we could count any footage in the credit sequence as some shots were tweaked to be fancier, like the blinking dashboard lights in Seasons 1 and 2, whereas K.I.T.T.'s dashboard never blinked in regular episodes, for example. Here's the screen shot just for reference:
To me, this ultimately becomes a question of just because nobody ever actually
said K.I.T.T.'s top speed in the series, does that mean he doesn't
have a top speed? I think this is something that can be established by "reading between the lines" so to speak and the Bible only meant to never outright say the top speed.