Ya, you will burn through the clear coat for sure. The best thing, like TimmyG said, is use the least aggressive option first. If they are small scratches, your kinda going to the extreme with D300. I would try maybe Menzerna P106 or even P085rd (i don't know the new #'s and am too lazy to look them up).
Another thing to consider is, maybe using a glaze. Sure, the defects will still be there, but if its a daily driver, your better applying a glaze every so often then removing the already thin clear coat. Its all up to you and what you want, but I find that I can live with the defects being covered up better than having to repaint the car.