Hi All, Got the m3 couple weeks ago and feel the heat from the sun coming through the glasses is pretty noticeable. Start researching what can be done to reduce solar heat. All the info seems to point to window tint will help. Before doing the window tint I want to find out how much solar heat rejection does the stock glasses offer but I can't find much information. So I decided to get a solar power meter and get the base line myself. This is the meter I got, SP1065 | BTU/Watt Solar Meter. The solar meter measures BTU/hr*ft^2 basically it's the energy/heat coming from the sun. I did a quick test by measure the power in front and behind the glass. It's not a scientific project but I did repeat the test multiple times for each glass. I feel it's a reasonable ballpark figure. Just want to share in case someone is interested. Location Outside of glass Inside of glass Reject rate Driver side 300 77 74% (This is south facing and at 2pm in San Jose, CA) Top front 194 4 98% Windshield 188 52 72% I tried to measure at the same angle but again, it's not a precise measurement just a quick measure to get an idea.