You can use the embedded search engine to find information about socket specific heatsinks.
I have the original Thermalright Ultra 120. Works for me.
I lapped my heatsink and cpu just see if I could do it. My results were excellent. Actual test results that I looked at indicate mixed results. I would say it's probably not worth the time and effort if you are not a hardcore gamer into extreme overclocking and serious tweaking for a suicide mission to save the galaxy from alien invaders. Instead concentrate on case ventilation, airflow, and cooling.
Rather than weight limits, I would say it is possible to tighten mounting screws too much. The result of overtightening can be a disaster.