is it a r350 or r360 core? some programs lie about it, to find out you might have to look at the core itsself. r350 = 9800pro, r360 = 9800xt in disguise.
The stock heatsink is pretty weak. You might not get a very good overclock using it and most certain the core will be pretty hot if you do overclock using it.
shim removal ins't adviceable... Shim really protects the weak ati core well.
Ive chosen to mill/file the edged of the coler... Now the ati core has direct contact with the cooler plus the shim is microts away from the cooler There to catch any bad forces!