You need the
Ghostcar mod and
Ghostcar Patch.
You can read about the Ghostcar up there, but I wasn't able to find info about the Ghostcar Patch, so here goes:
Ghostcar Patch is a tool to record a lap from
spr's as your ghost car.
Instructions:
1. Run the Ghostcar Patch
2. Run LFS in window mode
3. Select the spr replay
4. Select a static view like the cockpit view.
5. Pause the replay before the lap you want to be recorded starts
6. Press Record on Ghostcar Patch
7. Unpause the replay
8. Don't change camera view while lap is being recorded
9. Done.
Use "/ghost drawpath" command to toggle patch (racing line) visibility on/off. "/ghost drawcar" does the same but for the car itself.. ther are more commands - check the page.
Ps. Ever since Patch W, Ghostcar is reflecting oddly - It's not showing up in my rear view mirrors, but instead shows up on the intrument panel glass.. hmm.
Also the ghostcar itself may look different than what was actually driven - just ignore these small issues. Works well enough though.