There are answers to common questions about TORCS: 
In the PDF-Version of the TORCS tutorial (C++) are bugs (Wrong images, missing chapters), so use the online version as reference.
It is very easy to create tracks for TORCS. We can do it in two ways, with surroundings and track only. This could help while testing the vision part. So we are able to produce situations we want to analyse in short tracks.
To create objects along the track, I used AC3D. It is intuitively usable, much faster to learn than blender.
TORCS uses only one cpu, with a multi processor board we allways have 50% taken from TORCS (to get as many fps as possible).
Here some facts:
1. TORCS gets all information needed to display the world from ASCII files in the 3D-format "ac". The track is generated from the helper programm trackgen reading the track's definition from track.xml file and is written to a track.ac file. This can be modified with a program like AC3d (or blender) or an programmed object generator we want to use to fill our world. The result is the world without the cars. It is static!
2. TORCS gets all Information to display cars from ASCII files in the 3D format "ac". They can be designed with AC3d or blender. The properties are set in xml-files (cartype or category, car and driver). It is static too!
3. TORCS displays the drivers view to the world and other drivers by moving a camera through this world, placing the cars at correct positions in adjusted directions.
4. Our wrapper knows all we need! All we need is the position and rotation of the drivers camera(s) and the position and rotation of the opoonents. This is content of the data we get from our wrapper. The rest we can initially read from the ASCII files as TORCS does!
To see an AC file, check out these tools. If you get a binary running on on Linux, check it into our repo! http://www.inivis.com/resources.html
Lets write a separate C# programm able to read the ASCII files and move cameras in this world. Let's use our wrapper's partner at the C# side (the Dispatcher object) to send the cameras and opponents position and rotation to it. That's all we need.
TORCS does the simulation in the simuV2 or simuV3 library (dll/so). The rest is stuff: Reading files and calling the library (or unneeded like sound and display, things we can neglect.
Instead hacking TORCS we should write a simple programm, calling the simuv2/v3 to get fast results. Later we can replace it by a own physics modell using the same interface.
We will have a clear segregation of functions. The interfaces needed are known (let's do it as TORCS does for a version 1.0) We dont' have to write code dealing with different operation systems. All code can be written for mono. We are free to do all like it is best for us and our later objectives. We can use different modules parallel (i.e. our new physics (as dll/so) and the simuVx libraries) to compare the results. All later needed modules (extended motion planning, recorders, learning loops with random noise generators to simulate imperfect sensors etc.) will not have interfaces to TORCS. This means, we dont' have to write any line of code temporarily used.
Setting aside graphics, torcs is race management / UI and physics / simulation.
We can attack each problems separately. We can plug in a new simulation engine we call from old torcs, or write new torcs calling old simulation engine.
However, we should have Ogre / Tao up and running before we re-write the management / UI portion. We need a C# solution for creating widgets and drawing text, etc. What format we store tracks and cars in is influenced by Ogre.
View of the AI modules (rules, learning)
The AI modules get all information about our position, rotation and movement relative to the world (track) and opponents, obstacles. Also it will get informations from traffic signs, crossings, or parking lots). Here we will decide, what we want the robot to do (Racing, pitting, parking, ..., slipstreaming, overtaking, avoiding, ...). Later we will have the possibility to switch between possible tracks to come from the current position to the target.
Motion Planning's view
At this point we know all (what we want to use). We know where we are and what our current movement is (relative to the world and other relevant things). Also we know what we want the robot do to, where to go to, etc. From now on, we will not longer add information but reduce it to what is needed for the following steps. First we will have to give the known information about the track and obstacles (opponents), our position, rotation and movement to the track generator. Later we can switch here between road based and offroad driving as well. This is, why I split Motion Planning and Track Generator. For offroad driving, we would have to use another module.
View of the Track Generator
Here we try to estimate the parameters of the track, used later for the driver. Assuming we are on the road, we had to get back the information we got from TORCS but don't use. In our estimation (model of the near world), we will calculate a racingline to be prepared to all, what might come up. If not racing, it would be using the right lane to be prepared to turn at the next crossing, to be able to park in the next parking lot etc. The model is kept until we got newer informations from the former steps.
The drivers view
The driver has to decide in realtime (50 times a second), how to steer (steering angle, acceleration, brake pressure, gear selection, clutch) the car. Instead of the TORCS information it will use the model provided from the track generator. It got additional information based on the rules, whether to try to overtake or to keep slipstreaming etc. Also it uses the on board sensors (engines rpm etc.).
And than we are back to our TORCS interface.
For version 1.0 I think we can use the UI from TORCS to start a race.
What I tried to reach is, that the modules can be programmed and work relative independent (and be replaced with an other approach if wanted).