Tangs!

Hello again everyone! So I have been doing a TON of research on tangs for awhile now. I am having such a hard time deciding which tang to start with in my 150 tall reef tank. I really like the kole tang, I am also looking at yellow tangs however I have heard they are not a good tang to start with because they become aggressive. I really think I should only have two tangs due to the size of my tank but I'm really not sure...... Looking for some advice...... Thanks!