Besides knowing you want to see cars and girls, do have have any sort of itinerary yet?
Where you flying in to, and how long you staying?
For girls, they are everywhere. Half the population is female. You can't miss 'em!
For cars - countryside & suburbs.
General info - http://www.japan-guide.com/
Just a few things for now....
Tokyo Station TOMICA SHOP
Roppongi Hills - fun nightlife with foriegners - not my scene, so never been.
Harajuku for the latest youth scene.
Akihabara for electronics and more.
Twin Ring Motegi & Honda Museum
Ikaho Automobile Museum
Maehara 20th Museum
Michael - Collector of Toyotamobilia ~ www.toyotageek.com
Tomica Fan Club ~ www.tomicafanclub.com