Why don’t you just open up your last car model and try for yourself? It’s fine as long as you just look at your model. It’s a slideshow as soon as you try to move a vertex. I don’t think I could get any significant work done like that.
I mean, you could probably work with it if you habitually break up your model into many small objects, but I don’t. Even then, 2000 faces, where it becomes unusable for me, is a really really tight budget that has no place in modern CG except as a personal challenge.