ikilldinosorurs

i have an 04 rx8 manual 6peed bassically stock just got the clutch changed to a speck stage 2 . clutch is extremmly soft and it makes a weard noise in 6th gear almost like air or the exaust . when i add a littl more gass it gose away . i dont know what it is. the transmision fluid was also changed at the sme time the clutch was changed.