Other World Computing (aka OWC or MacSales.com) shows the 2010 mini can go to 16gb. My belief is you will see some improvement going from 8GB to 16GB.
Another upgrade to consider is a SSD drive but I would still do memory as well. I just went from 12GB to 18GB in my MP and have seen the benefit there.
Here is a link to the Mac Mini memory page for OWC: