What I did:
1 - Take out both heatsinks, clean them, lap them and apply arctic cooling 5 thermal paste. Granted, I have a 1.6 xbox, so no fan on the heatsink.
2 - Swapped the 60mm fan by a Noctua 80mm fan, cutting out the fan corners to make it fit, and the xbox metal grid to maximize airflow.
3 - Since I swapped the HDD for a 7200RPM 120GB, I also cut out the back of the HDD tray so my 80mm fan sucks air from the tray, cooling the HDD.
So not much more than you did, and like you, I have temps at 55/45, which I too think is fine.
This post has been edited by cricri_pingouin: Apr 9 2012, 03:49 PM