For something a bit different you could always make your own stickers. I've noticed that a number of Porsche owners have simply submitted a picture (or two) to sites such as
Zazzle | Custom T-Shirts, Personalized Gifts, Posters, Art, and more and then ordered stickers featuring said pic.
Zazzle's fine print:
Square Sticker
Create custom stickers for any occasion! Customize a variety of existing designs or add your own photo, logo or text. The perfect choice for any message or design, square stickers are great for brand promotion, special mailings, and scrapbooking.
Available in 2 sizes
Large: 3" x 3" (6 per sheet)
Small: 1.5" x 1.5" (20 per sheet)
High quality, full-color, full-bleed printing
Scratch-resistant front, easy peel-and-stick back
No minimum order
Other sites such as
SublimeStickers.com - stickers, custom stickers, vinyl stickers, free stickers, wall graphics, bumper stickers offer other sizes.
Hope this helps. The 'sticker' below is from zazzle.
