the short answer is that you have about 3 weeks to get it in, and registered, before the new rule comes into force. After April the first (appropriately: April Fools' day
) new frontal impact requirements come into force. As Japan introduced these standards between 1994 and 1996, pretty much any Japanese car pre-1994, and many pre-1996 won't be allowed in any longer. Have a look on
the SDU forums - it's been discussed heaps.