Here's a quick video that shows what Ostexo is talking about:
The key for your cars will be going back to your initial method of layout and defining "sections" that you will do your layout "past' (extending your modeling curves and panels past each section)....
That should also keep your modeling techniques congruent so you aren't creating disparate surface structures that you have to try and blend....
There's much to talk about your model, but the basis would be that....
""""""""That said the car looks great, even with the sharp edges """""""""
