Here's twenty interesting possiblities and solutions that deserve a
What if?

1) What if KARR had went head on with KITT in Trust Doesn't Rust?
Then KARR would have probably turbo boosted to avoid the collision. Michael had overrided KITT in this situation, so this would seem the only possibility.
2) What if Bonnie had appeared in Goliath and Goliath Returns?
Bonnie would have thought of the laser earlier then April. Not to mention, in Goliath Returns, I honestly think she could have won Garthe over with her charm.
3) What if KITT's pieces had not been disassembled in Knight Rider 2000?
Michael would have put KITT back together again and maybe with a few modifications be the car we all grew to love.
4) What if NBC had let Knight Rider go into syndication for the 1986-1987 season?
My guess is that we would be talking about 6 seasons of Knight Rider, not 4.
5) What if Stevie didn't die after being shot at the altar?
 Stevie is alive and well. She was in the witness protection program, remember?
6) What if Wilton never died?
You always see Devon coming from some office. What if it was Wilton he was chatting with?
7) What if Tonya Walker faked her own death?
An interesting 5th season opener, ha?
8) What if KARR was chosen as the car by Wilton and KITT was never made?
With some modifications, critics might have embraced the 1st season more as a car with no human emotions or  a show about you average car parked outside.
9) What if in KITT vs KARR, KARR never suffered the laser fire and then turbo boosted?
NBC would have spent the equivalent of the amount of the entire first season's budget for this one shot.
10) What if Goliath did not plunge off the edge of the cliff in Goliath Returns, killing both Garthe and Adrianne?
It appears that Adrianne survived the crash...fast foward to season 3...
11) What if Bonnie gave into Michael's advances in Season 1?
Can anyone say the word "Cancellation"?
12) What if Michael had returned to his family in Knightmares instead of an old address?
Maybe then we could have Larry Anderson reprise his role.
13) What if Stevie had appeared in a season 3 episode?
Then it wouldn't be a triology now would it?
14) What if Michael would have married Jennifer Knight?
The family is already screwed up enough..lets not go there.
15) What if Bonnie and April had to work together?
Probably would have been the best Knight Rider episode to watch ever.
16) What if RCIII had been acutally given intelligent conversations?
And take away from KITT? No way man!
17) What if KITT in KILLER KITT had turbo boosted through the reception?
That would have been the point where Brandon Tinkeroff at NBC would start bouncing checks for going over budget on the show once more.
18) What if KITT could not turbo boost at all?
That's like asking the General Lee not to jump cliffs.
19) What if KITT was assigned for light duty after Michael gave up in him in Junkyarddog?
Then Michael would have gotten his long overdue vacation.
20) What if Michael actually got paid a salary?
Appears he is always borrowing money...hmmm..