hello :) i link for you a very good site, where you can download legion of chess engines, this chess engines work via arena chess interface (gui).

Engines: ccrl 40/40: http://www.computerchess.org.uk/ccrl/4040/

ccrl 40/4: http://www.computerchess.org.uk/ccrl/404/

Arena 3.0 : http://www.playwitharena.com/?Download:Arena_3.0

just tarrasch : http://www.triplehappy.com/

were can I get this Tarrasch chess engine.