Vibration - someone please help!

Hi guys,

I've recently had a new clutch and exhaust system fitted on my Skoda Fabia 54 plate classic.

When I had the car back the bite was ridiculously high and I had to have my clutch pedal really high, it also vibrated like it was going to stall, but never did.

I was driving today and I heard a catching sound and a huge vibration, I pulled over and behind my battery there is a black box with a pipe coming out going to my engine, it was vibrating crazy. I couldn't stop it however I tried, when I revved, the vibration got better then when I was idle or slowing down it got really loud again. It also vibrates like mad when I'm reversing.

Anyone have any ideas what this could be?!

I know there is a load to read but I'd be so greatful of some help, I'm not ready to part with her yet:-( Thanks guys.