Cheat:

 Buy in the 1st year no MOTOR and then you get a free Nissan motor.
 You don't have to pay for it!

 From Mike Makkink, m.makkink@dosgg.nl

HexCheat:

 Using a hex editor, change hex offset 2698 to read 804a5d05 in the
 savegame. If this is done correctly, you should get 90 million.