In the mission where you have to exchange 3 formula racing cars,the red one is caesar 8 racing or something,after you finish it,you can get the red formula car close to the prison,just park it at salieri's bar under the wooden roof where you usually learned how to unlock a new car there, the roof is at salieri's back door right from it. There will be no picture for this car if you wanna use it in freeride but it will be unlocked.
Now to the exploding celeste problem.
I can't do it since even at 90 kph Tommy still reacts to explosions and the mission is impossible to do due to the higher framerate than my old pc.Think the framerate opened with fraps is showing around 50,the framerate would need to be 20 i believe to easily finish it since the bomb don't drop as frequent then, what i can do is use fraps free version and record at a 20 fps limit every 30 seconds until i reach the goal, with 2 attempts i didn't have luck to actually make it, but i believe it's doable with fraps.

[url=http://mafiagame.wikia.com/wiki/Talk:Exploding_Celeste]http://mafiagame.wikia.com/wiki/Talk:Exploding_Celeste[/url]

Trying to bump and see if the topic reappears.
Also if you have nvidia you can use nvidia inspector to limit framerate look at link talk:exploading_celeste above.
Edit: actually i managed to beat the exploding celeste one by simply increasing resolution for game and antistropic filtering to x2 and then i didn't have such problems with this mission.

on windows 8/8.1 and 10 you need a custom d3d8.dll that support fullscreen mode (and not borderless mode), this to allow a fps cap (i suggest 30 fps)

That's right solution of caesar 8 racing problem,Thanks a lot.
About exploding celeste problem you can try the widescreen fixes pack to limit the framerate in 30fps:
[url=github.com/ThirteenAG/WidescreenFixesPack/releases/tag/mafia