from the info this case comes with 2 fans only, one on top(140 mm) nd the one from back the exhaust one.u can add other 2 fans in front nd 1 on the side panel of the case.if u want to add them it's your choice now depends on what hardware u want to mount in to it.me i always liked more airflow inside my case.from the looks of it i will add the optional ones too just to make sure that i have the good airflow runing.
I own an Antec 300 case and it comes with a top 120mm fan and a rear 120mm fan. both fans are positioned to pull air out of the case.
On a side note: I would not suggest the Antec 300 for purchase because it is an outdated case in terms of offerings, for 50-60 dollars it costs you can acquire a much better case. Although if you plan on making case modifications then this might be your best choice because its simplicity makes it easy.
Pros- Very Sturdy
60 dollars can get you better cable management with grommeted holes for cables.
I HAVE THAT CASE...
It comes with 2 fans:
140mm fan on the top
120mm fan on the back
(Both have adjustable speeds)
but for the best airflow, I have installed another 2 (120 mm) fans in the front and 1 (120 mm) fan on the side.
My system stays cool and I have my cpu overclocked to 3.6GHz.
Would you need to add more fans... no.
The two included will pull cool air into your computer and push hot air out. Any extra fans will just increase airflow even more which is great if you plan on overclocking.