do those cases really help......

because im getting a new chassis and i was wondering if i should get a TAC
and i know the big tunnnel will ruin the clean look??

I don't know how much those cases actually help, all you need is plenty of ventilation. Generally, if your case has 2x120mm and another fan on the side-panel, that's all you need.

One of the better cases for airflow out right now, I think, is the TT Tsunami. If you're willing to cut out those stamped fan grilles, you get nice temps and the case still looks good.

i myself dont buy that crap about TAC, all you need is a roomy case, 2x120mm fans and a blowhole/sidepanel window (ducted to cpu) and ur set! go for an antec, TT, or lian li

It's more about how you setup your fans than how the case is made...but for lazy people who don't want to do this, I guess a "thermally advanced" case may lower your temps by a whole degree celcius. You're case (normally) isn't where your focus should be if you are trying to lower temps as long as you have decent airflow through it.

if you want fan space, the coolermaster stacker is where its at. the thing is absolutely huge