I spent a few hours tricking up a Lambo Gallardo in Forza 4 last evening, to celebrate my "promotion" to the Master's Series. Unfortunately, T10 forgot to beef up the decal list - heck, it seems to have even fewer than Forza 3 has! At least in the Lamborghini page.
But thanks to the Livery Editor, it's so powerful that you can make your own decals, save and share them. In fact, I had spent too much time fooling around with the Gallardo as it was, and I wanted something stylish as a main sponsor. Off to the Storefront I went to buy some decals - using game credits. But often I didn't need to buy a thing, many were free. Eventually, I found something interesting and slapped it on. If I wanted a complete livery, eventually I know I'd find several worth buying. If I can get MS's stupid photo system to work, I'll see if I can snap a pic of it sometime.
THIS is what I want in GT5, because no one team can make all the decals in the world, or make every livery I could want.
There are a lot of talented artists making excellent content for Forza, and they save me a lot of time and trouble for a handful of credits. You people who keep whining about My Little Pony and gonads need to quit being such babies. Unless you're Amish - which you wouldn't own a PC or game system anyhow, you live in a world in which you see and hear obscenity every day, and see ugly cars by the dozens. In the game world, you can shut this stuff off, unlike the real world. So get real, please.