Hi,
It looks like your building the car using nurbs which for your second model ever could be a bit of a handful.
IMO you should learn to make things in polys
Also it looks like your trying to put to much detail into the car to early
In my experience I prefer to model the car using polys all as one piece so that includes the windows and everything as a shell of the car once I am happy with the basic shape I extract the different parts and then add more detail in afterwards.

Just my honest Comments

Rob