What do you guys recommend I replace or add when I put on my 17% pulley?

 

Belt and plugs are all you will really need to safely use a 17% pulley.

 

+1
A few vendors sell kits....
http://www.waymotorworks.com/wmw-pulley-package.html

IMO a tensioner stop, Like sold by Detrot Tuned or alta is a good thing to do also...
And look closely at the tensioner itself....if it os over 5 years old or maybe 60,000 miles, might be worth swapping it out...the little strut on it tends to fail.

 

+1

Also check the timing chain cover gasket and front main seal for leaks. Another common failure.

 

Belt and plugs are all you have to have.
http://www.waymotorworks.com/wmw-pulley-package.html