Setting hits count to a high value wont affect your users’ page access time at all. The only time your server will suffer is when it is creating the view stats page. I don’t think it is going to be a big hit on mysql server but if you are not using compression on your web server, view stats page make take a long time loading.

Quickstats is set to log 400 hits the first time, but will it affect my server much if I use 9999 hits instead? Will the users feel the hit also?

Btw, love it really much. You did a real fine job with this one