Stats have stayed the same even after tuning

The stats 7.9 on both speed and handling before actually tuning gear box etc, I got the speed to 250mph and done tyres/ down force but the speed and handling stats remain the same.

Have I missed something? Any help be appreciated

The SHALB (speed, handling etc) stats do not change via tuning, only via building.

The actual top speed etc are affected by both.