www.amstuning.com ask for Ivan.
www.im-racing.com
Really any local machinest can order these parts and really are usually cheaper than any internet retailer you will find.
Pretty much of all the big piston manufacturers make them for the KA
Wiseco, Ross, Arias, JE, etc. all make pistons in various compression ratios for the KA
Pauter, Carillo, and Crower all make rods for the KA as well. All of which can be ordered from many people.