@SuicidalInsanity Thanks for the reply, Tonight I tried to battle the issue again, and found exactly what you were saying, Tweakscale (when resizing the OPT wings to 50% to fit the MK 2 size), gives the wings a negative mass. I was going to edit my post tonight, to clear this mod of the problem... who knew (still quite new to the game really). If I return the wings to 100% size, the aircraft flies normally (if not goofy as hell looking). I went into the config files for the wings, and added scale to the model (0.5,0.5.0.5) and the wings worked with no issue, It must be the math that Tweakscale uses to get into the negitives (not sure how the code works in KSP, but some kind of "If (M => 1) M = M - (M/2)" in there to prevent negative numbers.
As for the part, had no idea of the 'unfunness' of legs. I haven't dabbled in it yet, but i do 3d modeling (using 3ds max) but I'm kinda stuck at the conversion from a 3ds format to the KSP 3d format conversion. Would love to have some reference models as i do have some ideas for parts not yet in the MK2 Catalog. I've dabbled with code for years, and the config files are pretty straight forward, and it seems the modeling is as well (along with the texturing).
Anyway, thanks again for the advice on this error I'm having, even if I blamed the wrong mod.