hey up everyone..i got a magnex exhaust from a 172 for my cup a couple of months back and since it has been fitted if you have any passengers of weight in the boot (macdonalds) then there is a cathing noise that vibrates through the car especially when you go over bumpy roads...i took back to the garage and they said everything is fitted ok and there is nothing they could do..but its starting to really tick me off now..the exahust note is great so dont really want to get rid...any advise anyone? could it be cos the fitting brackets are different between the two cars as i have heard this in the past...help me giants of knowledge!!!!