Did anyone ever tryed the Kirschbaum Competition String?(http://www.tenniswarehouse-europe.com/descpageACKIRSCHH-COMPK17.html). Yesterday I hit with my coach racquet (Yonex RDS OO1) string with Kirschbaum Competition String and the power and spin is just awsome! He told me that a lot of guys down at the club (where Frederico Gil trains) use this string. Even Frederico' coach uses it! I ordered a pair from Tennis Warehouse!