i went with Madico 35% to match the factory tint. there is a slight difference. rear seems to be a bit darker.

I also did 35% in the front to match the factory tint and 50% in the back windows since they are already dark. The result came out pretty nice, with a tad darker in the back. The rep told me not to go anything darker than 35% if you don't want to get hassle by the cops. Madico is a good brand.