Hello and Welcome to Driver Madness Alex.
We're a fairly active community, although we don't get much discussion on modifying the games anymore. This is mainly due to the lack of time I have these days to modify the game and the fact that not all that much can be modifyied.
If your interested in modifying Driver: Parallel Lines I suggest you check out the Driver: Parallel Lines
Modification Forum.
I can ensure you it is possible to mod levels.txt.
There are a couple of things I've worked on changing in the past.
I have decided to list some topics of interest (related to modifying levels.txt)
Any Position [TWEAKING]
Get to any position within the game.
Note: Unfortunately the attachment feature is no longer available on this forum. Therefor the download will no longer exist. If your still interested I can upload it to the downloads section on Driver Madness upon request.
If you want to find out more information about levels.txt there will be a DriverWiki article on it sometime in the future. Unfortunately the DriverWiki isn't available for public release and it'll be quite some time until I can find enough time to write an article on it.
