I am sorry to be critical with only 2 stars but this mod/version really could do with some thoughtful work. I give 2 stars for the effort but the rest of the stars have to be gained by improvement.
The good thing about this sound mod are the exhaust pops, turbo blow valve noises, and the general engine rev sound sounding quite realistic, immersive and with minimal sound distortion at mid to high sound ranges.
The big negative I find when using this sound mod, is the exhaust sounds go awry at idle and loses all the realism. This could be improved by having the engine rev at 3000 rpm and using the sound generated at 2500 to 3500 rpm as the f40's idling point to help correct the weird exhaust popping speed. (I tried this and it seems to fix the crazy unrealistic exhaust burbling at idle although I have to keep the engine revving). The current muffler pops volume level is good for idle and it seems realistic for the car but the actual sample sound itself seems like its running at the wrong speed. This really needs to be fixed.
The next thing I found that breaks the sound immersion, is the actual motor noise at high speeds. I would expect the engine to be pretty loud and present at such high load in any car, but this sound mod goes the other way by getting more quiet. It seems weird. I would take a wild guess that it may be the result of trying to clean up excess wind noise at high speed, but maybe the next step is to increase the engine revving volume at high speed but cut out as much bass tones as possible if the wind noises appear too loud.
Apart from these two negative issues, I think that the sound mod has great potential to be the best of the lot for the F40 sound mods and could even beat the original file if the issues are fixable.