I've had three of them! I don't remember if fixed gear was an option on that one. You could do it yourself, if you wanted.
Definitely do the servo change on the ailerons!
And get a 91. You'll be happier, I think.

Grass is not a problem, 200' will get it off, but that depends on how heavy you build, of course. My last one came in at 9.5 pounds, while I did not fly that one off of grass, it got off the pavement in maybe 100', with a 77, not a 91. Check my gallery for pics, and do a search, I think I posted some stuff about it.