You don't need this to get into a certain group. But it makes trading or building a car collection much easier.
Let's say you have a corvette c2 race car and you want to dupe it for any reason. All you need is a USB stick. You backup your GT5 saved data onto it, send your car to your friend, or an alternative account of your own if you simply want more than 1 for yourself. Then you reload your saved game data from The stick and wala, you now have the car again, along with whoever you sent it to.
You can do a Google search for "duping cars in gt5" to find step by step instructions with pictures.
It doesn't bother me whatsoever and is probably why you didn't get an answer yet, but you will probably catch some flak for not using the search function. 98% of your questions will already have multiple threads on the matter on this forum. Sometimes you have to sift through some obviously dumb "this Is how it works posts" but you can generally see who knows what's what. Just a heads up.
Also some of your cars thumbnail pictures will disappear after you do this. Just go to that car in your garage and click triangle, you will see an option saying generate thumbnail or something like that.
Good luck.
