Cars:
1968 Dodge Charger R/T (dream car)
1985 BMW 325 sedan (because I had one and loved it)
1968 Shelby GT500 Fastback
2013 Shelby GT500 Super Snake
Alot more classic 60's, 70's, 80's and 90's Le Mans race cars.
BMW M3 E30
BMW M1 E26
BMW M5 E28
BMW 3 Series E21
BMW 3.0 CSL
Ferrari F50
Ford GT40 road car
Mercedes-Benz SLS AMG GT3
McLaren MP4-12C GT3
Ferrari 458 Italia GT3
Ford GT GT3
Aston Martin DBRS9 GT3
Porsche 911 GT3 R GT3
Lamborghini Gallardo LP600 GT3
All cars premium of course, and with lots of customization.
Im sure there are lots of other cars I want in GT6, but this is all for now.
Tracks:
Complex String
SSR11
Bathurst (more or less confirmed in GT6)
Pikes Peak hillclimb
60/70's Circuit de la Sarthe
Hockenheim
Dubai Autodrome
Nardo Ring
Rudskogen (Norway)
Vålerbanen (Norway)
Top Gear test track (with the whole runway and everything)
Circuit Zolder
Yas Marina Circuit
Shanghai
Monza Oval
And all classic Gran Turismo tracks.
All tracks with weather and day/night features.
Probably more tracks which I can't think of right now.