In cgminer it says 98Gh/s - 103Gh/s. However, the slush's pool site I have now been able to over 80 Gh/s. Is it just me, or just something on the site?
For example, right now I see "78.544 Ghash/s"
I think you may assume that the figure in CGminer is correct. The figure on Slush's site is back-calculated from results submitted (the site has no way of knowing your true hash rate). What does CGminer say your difficulty per submitted share is? You might want to try setting that slightly higher on the web site, e.g. if your difficulty is running at 48, try setting it to 56 and see what happens. My own S3+ rigs are set to run at 256 minimum difficulty, which gives me better results than letting the pool set it dynamically.