1st video dead
2nd video sounds pretty normal, maybe something a bit loose causing a light rattling noise like the bumper sagging or a bottom cover not fully secured. It could also be totally normal and everything is fine. That light 'rumbling' could very well be the noise the engine makes at part throttle under those conditions, it doesn't sound 'wrong' to my ear.
Ask in the local section for a good shop, take it in for an inspection to make sure everything is buttoned up, someone who knows these cars should be able to spot a missing fastener or something out of place pretty quick. Should be <$100 which may be well worth it vs. the time you'll spend pulling your hair out if you don't know what you're looking for. If they say it's good, trust them and accept that you bought a noisy cheap sports car.
