Kosola is presumably a friend of Petteri, and possibly the player's. He is apparently stuck in front of a computer somewhere.
On the Puskaradio radio show, an old lady calls claiming to be Kosola's Grandma, and rambles on about how she hates mopeds and thinks they should be illegal.
It has been speculated that Kosola is the driver of the Techno Victra, which is not true because K. Nygren is the driver revealed in this update. Plus, it is said by Petteri that "Kosola has been in since he got the computer or something" which implies Kosola is playing on his computer and clearly not doing much else.