You would need to change:
1. The transmission itself. This is the most expensive part of the conversion, and it can cost several thousand dollars.
2. The driveshaft. The driveshaft in an automatic transmission car is shorter than the driveshaft in a manual transmission car. You would need to replace it with a longer one.
3. The clutch. The clutch is a part of the manual transmission that engages and disengages the engine from the transmission. You would need to install a clutch pedal, a clutch master cylinder, and a clutch slave cylinder.
4. The shifter. The shifter is the part of the manual transmission that you use to change gears. You would need to install a shifter, a shifter linkage, and a shifter boot.
5. The wiring. The wiring in an automatic transmission car is different from the wiring in a manual transmission car. You would need to rewire the car to make it compatible with the manual transmission.
In addition to these parts, you would also need to have the car's engine management system reprogrammed to work with the manual transmission.
In most cases, the time, effort and expense in making this kind of conversion just doesn't make financial sense. It would be better to sell the automatic car and buy a manual one.
