So i bought a moshi cleargaurd for my brand new 15" MBP and i kept reading about possible heat build up because of the actual protector covering up air vents under the keyboard. Here is the test i conducted: Laptop Completely Charged and plugged in. Safari idling on apple.com Amsn (msn messenger) launched and idling Itunes playing 14 songs, Visualizer turned on (not fullscreen) Laptop was set to Better performance (Aka using 9600 gtm instead of 94000 I left the laptop in this condition untouched for 2 half hour periods, half our with and half out without the moshi clearguard on the keyboard. The laptop was also set to not fall asleep. With moshi clearguard: HDD: 34 °C CPU: 71 °C CPU Heatsink: 56 °C Enclosure base: 35 °C Enclosure base 2: 35 °C Enclosure base 3: 34 °C Gpu: 60 °C Gpu Heatsink: 73 °C Fans running at 2450 rmps Without the moshi clearguard: HDD: 34 °C CPU: 70 °C CPU Heatsink: 57 °C Enclosure base: 35 °C Enclosure base 2: 35 °C Enclosure base 3: 33 °C Gpu: 61 °C Gpu Heatsink: 72 °C Fans running at 2400 rmps In conclusion, i theorize that the moshi clearguard barely affects if at all the running temperature of machines.