The rattling sounds like there is a really tiny ball or rock rolling inside of the hilt right? That is the motion sensor, I believe it is a ball of mercury that rolls around to get the sensors. Don't worry about that.
For the clash sound, my Vader takes a bit to get clash too. If you hit the side of your hilt with your hand, you will get the sound better. The saber also takes a bit to warm up to being hit. After about a month, you should be ok.