Z1 motor sports performance clutch and fly wheel replaced now it makes a sound like metal rattling after car has been driven for a little while and I let out the clutch

 

Not sure without a sound file. But could just be the sound of the clutch. Our factory one uses a dual mass flywheel that absorbs alot of the sound but can still be heard as a rattle at times especially in a position where the noise can be amplifier off a wall. Z1 uses a traditional clutch that is very noisy with some saying it sounds like a diesel truck. ZSpeed has a quiet disk option that quells the sound somewhat closer to the OEM clutch. Depending on who installed it you might want to have it looked at but it's possible that it's normal.