I have a 2000 Boxster with 106000 miles on it. When I am driving the stick shift bounces around a little bit when I hit the gas. It never pops out of gear but I am wondering if this is normal. This is my first car that is Manual. Is this normal and is there a way I can tighten this up.

 

I think it's normal, mine does the same thing and it's only got 20K miles on it.
It's caused by the engine (and transmission)moving on its rubber mountings as you get onto and off the throttle which imparts movement to the gearshift linkage.