Well apple put thermal paste on it. It is a G4 and runs pretty warm. I guess you could sand the heat sink if its not already, as the paste is just for air gaps anyway. The original assembly put too much paste on as usual and you dont need alot. I dont understand why that would be a deal breaker as you can wait till reassembly to put paste on. Its the white paste and can get it pretty cheap at radio shack. I wouldnt chance going without it but thats just me. Its pretty tight in there so I suggest cleaing the small fan which is all the way at the topof the dome.