An article in Vette magazine mentioned that the air cleaner on a 2008 C6 is intentionally restrictive.  So should I change to an aftermarket less restrictive air cleaner?  Will it give me a noticeble increase in power?  About what percent of power increase will it provide to me? Which afermarket product would be best for me to purchase?  

Replacing your C6's stock intake tract with an aftermarket cold-air or ram-air system can add as much as 12 hp at the rear wheels on a stationary dyno (and possibly a lot more at highway speeds). I suggest that you do some research to determine which kit best suits your needs, as each one has its own unique set of pros and cons.  

Great advice... I just picked up the K & N kit to add to the Diablosport Predator Tuner.  Spring Mountain is next.  Learning to control and handle my car well is probably the best performance enhancer for me.  I have not been to a performance driving course since 1981.  I am more than a bit rusty.  I have not run a road course since about 1985.  1/4 mile runs 3-5 times between 2003 and 2007 adds to my subjective "rust" perception.  Bolt-ons are nice, but a rust remover is probably more important for me.