RE: challenging speed plane modification
why are you thinking in that plane? A Nemesis F5d or Excite F5d I think would be better airframes for speed than the supersonic (1650mm wigspan is huge!)
The Nemesis has already made 200mph electric [link=http://www.rcgroups.com/forums/showthread.php?t=491932]TheTick Nemesis thread[/link]