This mod has tons of potential. The externals are great, they have that signature GT40 sound overall, the only thing it might be missing is a proper upshift sound.
The internals could use some improvement though. It has a nice bass, specially when off throttle, but specially on throttle and on high revs the sound overall is a bit obscured and not as involving as it could. You can actually hear pretty constant pops onboard when off throttle in the real car. And the internals could also use a proper upshift sound.
There's a youtube user by the name 19Bozzy92 who has uploaded a video on the GT40 MK1 with tons of onboard footage. Maybe you could get some pretty solid onboard samples from there.
All in all. This sound mod is ALMOST THERE! I can almost smell the car itself. But there are some details that hold it back for me