March Cosworth 85c Indy Car

I’m starting a new project for fun. 1985 March Cosworth 85c Indy Car. Here is a quick first rough render of some initial blocking. One thing I always struggle with in modeling (still a newbie in my opinion) is how to approach hard surface modeling. How far should I go before applying sub-d surface modifier? Or, do I even need to? In this case, the nose
of the car is a separate piece, it extends about 3/4 the way back and includes the back of the cockpit, as is the windshield, both have sub surface applied, but I still have more to do on those parts. The cowling (the back top half of the car has no sub-d, as you can see by the gaps and square angles. Again, i still have much to do on that part too, same for the side pods. Any tips as to when in the modeling process I should sub-d vs. how long to poly / box model without it?

As always, thanks to the great Blender Community!

update…working on details / modeling still…

a little more detail…

What I do is leave subd on, then just toggle it as viewable/not in Object and Edit modes. That way I can watch my underlying topo and also see what the finished product is coming to look like.