Note that ^^ link is only updated to v1.15.
The following has been upated in v1.17...
04/09/2018 Update Notice - v1.17
Gr.1
Audi Vision Gran Turismo [Power Ratio : 85%] [Weight Reduction Ratio : 80%]
Gr.3
Chevrolet Corvette C7 Gr.3 [Power Ratio : 104% > 103%]
Dodge Viper SRT GT3-R '15 [Power Ratio : 84% > 83%]
Lexus RC F GT3 prototype (Emil Frey Racing) '16 [Power Ratio : 108% > 107%]
Lexus RC F GT3 (Emil Frey Racing) '17 [Power Ratio : 108% > 107%]
Nissan GT-R GT-R NISMO GT3 N24 Schulze Motorsport '13 [Power Ratio : 109% > 110%]
Volkswagen GTI Vision Gran Turismo (Gr.3) [Weight Reduction Ratio : 104% > 103%]
Gr.4
Alfa Romeo 4C Gr.4 [Power Ratio : 103% > 102%]
BMW M4 Gr.4 [Power Ratio : 98% > 99%]
Lexus RC F Gr.4 [Weight Reduction Ratio : 102% > 103%]
Mazda Atenza Gr.4 [Power Ratio : 105% > 104%]
Mercedes-Benz SLS AMG Gr.4 [Weight Reduction Ratio : 105% > 106%]
Renault Sport Mégane Gr.4 [Power Ratio : 99% > 100%]
Toyota 86 Gr.4 [Power Ratio : 100% > 99%]