I agree with Scott's assessment. I am not sure what the fascination is with pushing the RV-12's speed and gross weight up beyond the baseline design requirement for LSA compliance. If your mission profile requires a higher gross weight or faster speed than the LSA limits, Van's does make the RV-9 which fits nicely above the LSA slot. I operate my EAB RV-12 (non-Rotax engine and IFR panel) within the airframe design limits, although I do occasionally push it near the VNE limit during descents.
I am sure there are those that operate RV-12s in the designer's reserve margin, and Van's has a history of not condoning such operation on any of the RV models.
John Salak
RV-12 N896HS