Here's my opinion:

Keep the Tundra for towing the race car.

Keep the Highlander as your family vehicle. See if you can apply some of your income tax refund to the principle to pay it off faster.

I'm assuming that your dh uses the 1990 Toyota as a more fuel-efficient option to the Tundra for driving back and forth to work. If so, keep that or put a new motor in the 2001 Toyota and sell the 1990 one. Or you can try to sell the 2001 Toyota as a parts car.

On a side note, I'm kind of surprised that the 2001 Toyota has a bad motor. I thought that Toyotas were indestructable and lasted forever.

definately don't lease a vehicle what ever you decide it is not a good money move...check out suzie ormans reasons for this she says it is one of the biggest wastes of money....i agree with keeping the tundra and the highlander..