Noob question about gearbox tuning

[Ma1ne]

So I’ve used the suggestions from
Jeje6410 but I’m not sure how to adjust max speed. Do I just adjust the final gear or do I adjust the max speed. With just adjusting the final gear the car still seems sluggish. Hoping to get a bit more info on this

 

[praiano63]

Here is the best answer , it's from 2013 but still works the same. 100% valid .
Detailed Transmission Flip by our fellow friend Dr Slump....