I went over a speed hump a bit fast the other day as the lights had gone out and i didn't see it in time.

Anyway i get a rattling sound when i accelerate... It's not the exhaust.. any ideas?

 

Check the heat shields if you have an older model as I've managed to crack mine twice so far and I get a lovely buzzing/rattly noise when I lift off the throttle. mine was bust at the front offside, near to the raidiator. Get under the front of the car and have a quick look.