there is nothing to fix, its one of the few cars that keep the full manual transmission with clutch in the adjustable one. other cars that i know of are turn14 brz and pontiac firebird or something? Id love to see a complete list.
what PD should do is offer the choice for every car when using the custom gears.
but in the meantime and probably forever the M3 is for people who have a clutch pedal. solution: use the M4.
1: not what op was complaining out
2: terrible advice in any case. if that's what youve been doing you would have been better off by just using the max speed auto setting the game gives you.
what you actually want to be doing: raise final gear, set max speed to minimum, set 1st to minimum, adjust 2nd so it looks nice on graph between 1st and 3rd, max out top gear, adjust 4th and 5th so they look nice on graph. then adjust final gear to your needs.