100%… I got the T4 recently for 3x3… I wish I had listened to this same advise…
T6 will make you happer. I do like the T4 for my tent and it’s good enough, but as mentioned wish I got the T6 because it’s near dead silent 
On the lower settings and will still pull more air then the T4 on higher settings, which is not loud, but also not dead quite…
I concure with @DougDawson you should seriously consider the T6 over the T4…