Imo, the best way to feel out a suspension is on the street...not the track/autox where the difference will be harder to perceive by most. Even a full track would be better for comparing than an autox event, again, imo.
I definitely think that you can get 70-80% of the performance of Xida's from cheaper options but that 30-20% is the harder part to achieve and shows SuperMiata's experience/expertise. I encourage anyone not to take my word or the advice of any one person but to do their own research and make their own well informed decision, research is free but a uniformed decision can be costly.