nismo with the 'o' with flames coming out it, looks cool as a windscreen decal, 1mtr long along the top of the windscreen.
if you want to go nuts, another popular option is kanji style letter down the side, like a large 'Skyline' in jap symbol. just behind the doors on the rear quarters, on a angle.
I also sell an un-natural amount of jap performance decals (for the doors), look good on a jap car, but get smaller ones, no longer than 200mm long. Had 1 customer want a large pair of GReddy and HKS decals for his honda, was nuts