I have a few minutes left to explain how the bone changes work.
Your mesh is ready and bones are assigned to the body/wheels and doors, you renamed all meshgroups.
Wats left is its skeleton and your mesh and the basegame car
You can already extract your mesh with the unimesh plugin and load it in Simpe by right clicking the gmdc and choose replace but delete the basegame car first.
Use ctrl z to bring it back, works easier to find the correct bone.
In the bottom window in Simpe you can see a preview of the mesh and its bones.(textures are still screwed) and so are the bones.
Milkshape
go to side view of the car and select the rearwheel bone(the circle becomes red)(Model/select/joint buttons)
Click move button and fill in some numbers, like 0.3 in the z box, then click move
You see the bone move at the screen but still of the centre of the wheel, click ctrl z and the bone will jump back to original position.
Repeat these steps till you have figured out the exact number so the bones ends up in the centre of the wheel.(these could be negative numbers!)
Write this down!
Now do the same with the y box(if necesarry)
The x box aint important for the rear wheels.
You have written down how much the bone should be replaced in y and z direction.
Simpe,
Go to the cres file in your package and click the creshierarchie tab.
Look up the rear right wheel rot and click it, you jump to the cTransformnode
In the translation boxes you fill in the numbers you just wrote down.
NOTE, To make things even more complicated, the Y and Z axes are switched when you update the movement of the bone in the cres file.
So Y in Milkshape is Z in the Cres file and vice versa Click commit
Repeat for the left rear wheel rot.
click commit and save your file.
You can in the mean time extract your mesh(without the maxis car) and load it in simpe.
Go to the gmdc and look at the preview, if you have done it all correct the bones are now were the wheels are, centered.
Note,
When editing the bonepositions on the axes you sometimes need to switch positive and negative, use Simpes preview to check.
The next bone is the door hinge, called the door rot in the cres file.
Take a good look on how its position on the default car and reposition it on your own car by moving it.
You always can export the file and import it in simpe to see wat you have done.
Then the front wheels(r_wheel_rot i guess, forgot), same way, hope you can figure this out.
When done correctly you see something similar as this:
Oh, it is important that the 5.0 is as wide as the basegame car and that the seat and steering wheel match!!
I scaled your model in porportion but i had to extend the steering wheel and colum and move the seat forward to make it all fit.
This is really important before you start with the bones!!
You can not change it after you adjusted the bones, you then have to start over....