I think the list is extensive, and I know I'm going to miss some (or get some wrong):
Cars
- Both Ferrari F1 cars
- 2010 Mercedes Benz C63 AMG Sedan
- 2010 and 2011 NASCAR stock car models
Tracks
- Top Gear test track
Features
- Any GT5 photo location
- ability to change car horns
- Museum and associated cards
- Track Creator (to be released later on GT6)
- Shuffle races
- Ability to set car settings to default
- B-spec (to be released later on GT6)
-multiple air filter/intake choices
-OCD and UCD
- Gifting
Cars
- Both Ferrari F1 cars
- 2010 Mercedes Benz C63 AMG Sedan
- 2010 and 2011 NASCAR stock car models
Tracks
- Top Gear test track
Features
- Any GT5 photo location
- ability to change car horns
- Museum and associated cards
- Track Creator (to be released later on GT6)
- Shuffle races
- Ability to set car settings to default
- B-spec (to be released later on GT6)
-multiple air filter/intake choices
-OCD and UCD
- Gifting