Producer (2007) Gold: '80s Metal by Various Artists

Vocals (Background) (2006) Chameleon [Bonus Tracks] by Helloween

Producer (2005) Power Ballads Gold by Various Artists

Producer (2005) Rock Chronicles: The Eighties by Various Artists

Singer (2005) Final Experiment [Bonus Tracks] by Ayreon

Vocals, Producer (2004) Kingdom Come [Bonus Track] by Kingdom Come

Vocals, Soloist, Guitar, Producer, Guitar (Bass), Mixing (2003) 20th Century Masters - The Millennium Collection: The Best of Kingdom Come by Kingdom Come

Producer, Guitar (Rhythm), Mixing, Vocals (2000) Too by Kingdom Come

Guitar (Rhythm), Producer, Vocals, Mixing, Rhythm, Music Direction (1998) Live & Unplugged by Kingdom Come

Producer, Guitar (Rhythm), Mixing, Vocals (1996) Twilight Cruiser by Kingdom Come

Vocals (1995) Final Experiment by Ayreon

Vocals (Background) (1994) Chameleon by Helloween

Performer (1994) Finest of Hard-Rock, Vol. 1 by Various Artists

Producer, Guitar (Baritone), Bass (1993) Bad Image by Kingdom Come

Bass (Electric), Guitar (Electric), Vocals (1990) Hands of Time by Kingdom Come

Guitar, Vocals, Producer (1989) In Your Face by Kingdom Come

Guitar, Vocals (1989) Best Heavy Metal from Europe by Various Artists

Guitar, Vocals, Producer (1988) Kingdom Come by Kingdom Come

Producer (1988) Best of Stone Fury by Stone Fury

Vocals (Background), Guitar (Rhythm), Vocals (1986) Let Them Talk by Stone Fury

Guitar (Rhythm), Vocals (1984) Burns Like a Star by Stone Fury