Rune, what type of Spark you have? I had a Spark Dynamic with the Plettenberg Advance. Easy mounting since it is front mounted.
With a great airplane as the Spark I would not want to waiste a second on the motor and buy an Advance or Q80 (but only when I know for sure it fits). C50 is good choice as well, of course.
Volkert
not exactly sure wich type I have ..its not the last one and not the first with the contrabalance on the rudder!!
lots off great engines out there ..I think I have to do some seriouse thinking
C50 or Neu ..sure its great motors had some issues with a Neu ..so no more gear motor for me