Maverick, I have built and Flown the GP Ultimate and I can tell you that while it's not a beginners build, GP walks you very nicely step by step through the entire process. And it fly's superbly with the OS 70. A 61 would definitely make this thing a firecracker!. One note on the kit. I've seen 3 of them that all have the same problem (although it's a minor one). The landing gear is a little soft. Seems like every other time you land, you have to "Un-squash" the main gear.
Nav8tor, You really don't need anything on those wing struts, they hold up just fine!