As long as you matched your blueprints i wouldn't bother starting new, you're at a pretty good stage to start breaking apart chunks of the mesh to model in detail. Once you do start breaking apart stuff you'll probably be able to delete some edge loops that no longer benefit that particular piece.
Ye seperate meshes to start with....panel lines are a bastard. Model in the contour of the edge with a single edge loop. Once youve got that you can go and make the panel line as curvy or sharp as you awnt with support edges. One thing about your model, some more support edges along the sharper lines on the car will make…
Is the entire body one solid object? If so, never do that. You're setting yourself up for a world of hurt. The wireframe will become a real mess, it becomes increasingly harder to add and/or change things as the mesh gets more complex. Cut the vehicle into pieces, one model for the front body, one for the back, one for the…