I'm not 100% sure about what Kimi says but this is my best guess: "Aika jämpti!". That would mean something like: "That was pretty precise!". "Jämpti" is a word from the spoken language, it was actually funny to hear Kimi say it (if that's what he said) since I don't think young people use it that much. (I apologize to the Finns who use it on a daily basis, I guess I just called you old farts
).
After that Kaj says: "Alright, se tuli läpi puhtaasti, hyvä." That would be: "Alright, that was a clean run, good"
I didn't watch the whole video but in the end they discuss how the route had been changed (byt the organizers). Kimi got to use his favorite word "vittu" again (if you don't know what "vittu" means by now then shame on you
).
From that video you can really see the giant rocks they had to drive through. It's amazing to me that any of the cars survived that
.