I have the Lian Li / Lancool Dragon Lord K-60 case with the narrow side window. Ventilation, airflow, and cooling are very good with the stock fans. However, if you want to improve cooling, then you might want to consider creating a wind tunnel effect by adding a second fan to the front panel and installing it so that it lines up with the cpu heatsink and the case fan on the rear panel.
Here is a link to a web page with a few photos and an explanation:
http://www.johnnylucky.org/dragon-lord/index.html