Here are a few downforce options for GT3...
Front Downforce 1.00
25803328 9E74457C
Rear Downforce 1.25
2500332E 9E7445CC
or
Front Downforce 1.25
2500332E 9E74457C
Rear Downforce 1.50
25903B2C 967445CE
or
Front Downforce 1.50
25903B2C 9674457E
Rear Downforce 1.80
25903B2C 9E7445CC
or
Front Downforce 1.75
25103B2A 9E74457E
Rear Downforce 2.00
25803B2A 167445CC
or
Front Downforce 2.00
25803B2A 1674457C
Rear Downforce 2.50
25803B2E 1E7445CE