He spent part of his life in Germany and thus has strong ties with the German metal scene.

German Rock Hard magazine featured him in 2007 as a "forgotten guitar hero".

While living in Germany, he served as a session musician for rock band In Rags, gothic act Tiamat, and thrash metal band Grip Inc. For both Tiamat and Grip Inc., he played sitar, his second favourite instrument.

[citation needed] Yli-Sirniö originally joined experimental Finnish crossover legend Waltari in 1989.

He also replaced injured Swiss guitarist Tommy Vetterli (of Coroner fame) on some live dates for Teutonic thrash metal pioneers Kreator.