calling all celica st18/2/3 owners

[fatgtr]

hey all.
my st182 is making a horrible rattle when the car is cold. this happens when releasing the clutch, putting your foot to the floor, releasing the gas pedal quickly, or whenever changing gears.
have any celica owners come accross this problem before? my friends st182 also does it aswell.
ive been told possibly an engine mount or something to do with the exhaust.
any help really appreciated.