It all depends on your reasons for wanting to tint it that dark, I will tell you that 5% all around will be VERY VERY VERY dark at night. It will be very hard to see if a vehicle is approching an intersection with it's lights off, and it will make it very difficult for you to see ANY pedestrians. Also, keep in mind that the rear windows on a SC or CC are already at 19% (yes, believe it or not!) so you end up making that even darker than 5%. If you go with 20% on the front windows, it will match the factory tint exactly. I usually tell people that if you want your window that dark, consider replacing the glass with black, ABS plastic! It pretty muck works out to be that same thing and it's cheaper! :hehe: