Well a simple comparision should help you pick. Assuming you are considering either xida club sports or FCM non adjustables are they are within the same price range ill give you a quick comparison.
Xida clubsport
-great valving by one of the fastest miata owners in the country.
-Adjustable to various springs and driving conditions (rain, balance understeer oversteer, change of spring rate, etc)
-Extremly light aluminum body paired up with lightest and arguable most linear springs on the market "hypercoil")
-Stroke length that exceeed suspension travel so you will never bottom out the syspension which is a very harsh experience when it happens. (imagine you suspension stroke hitting a brick wall)
-option to upgrade to dual, even triple adjustable.
-AST shock which in terms of quality is superb.
-damping range soft as nb bilstien on the low end to harsh as double the rate of tien flexs on the high end. This alows the user adjust which way they want to comprise their suspension, more towards handling, or more towards comfort. And if you dont like a setting it takes a minute or 2 to change.
FCM fixed damping
-great damping valved by fellow miata enthusiast, with many positive reviews on this board.
-non adjustable in this price range, but damping allows +-100 lbs in spring rate.
-heavy steel shock oem length shock, either heavy QA1 or eibach springs.
-stroke length that works great with car is barely lowered (12.75 front, 13 rear) but ne lower you start running out of stroke. Car is prone to hitting bumpstops and not allowing suspension enough travel to function properly.
-able to upgrade to single and dual adjustable.
-Bilstein quality which is known to be precise, and durable.
Colesnotes for those that do not want to read the novel I wrote below
I have owed FCM's and consider them great coilovers, but in the end I have chosen to purchase Xida Clubsports as I believe they pack more bang for buck
A lil more in depth about both companies:
I can tell you that I have personaly owned a set of FCM's and sadly had to sell them due to financial reason at the time. I had to wait ten years and 11 months before I finaly recieved my shocks (well...maybe an exageration
but it did take Shaik 3 months to finaly deliver my shocks. Though through the entire time he always answered questions I had, and then some so I consider customer serivice top notch if your willing to wait X amount of months for your shock. Once I recieved the shock I was very pleased. I order FCM's in 550/350 flavour. They were everything people ragged about, very comfortable, great handling, and beefy design. I also upgraded to swift springs which cut down some unsprung weight, and gave the springs a bit more linear feel. Overall I was very happy untill I realized I didnt like how high the stance was, and also the 550/350 was a lil on the soft side more my iron butt. It took the car just a millsecond more then I liked to settle down in turns, which is in no fault of the FCM shocks, just my choice in spring rate. As for the ride height, when I tried to lower the car to where I like its looks (12.25 and 12.5) the shocks became much harsher over big bumps because it would bottom out, and the limited travel made the ride bouncy as the shock didnt have enough travel to work. So to my dismay I went back to 12.75 and 13 to get the shock working well again. Overall very good product, but given what I wanted, and at the same time ran into debt, I had to let them go. If not for the debt I probably would have kept them but it made the choice easier as I wasnt fully satisfied with the product.
In terms of Emillio;s customer service, after I solved my financial problems I decided I wanted top notch coilovers again and purchased some xida-s coilovers. The next day I called emillio to ask him when wil my coilovers arrive. To my suprise Emillio told me when but then fired a question back and asked if I knew his clubsports are coming out. I almost thought I was going crazy because here I am with full payment made a day ago on xida-s coils and emilio is questioning if the purchase is right for me. After talking to emillio about the small drawbacks yet huge saving of xida clubsports I asked for a refund. I really appreciated the fact that emilio didnt just try to push some expensive part down my throat but instead did the opposite and told me to save my money. On top of that for the next 20-30min emilio went through everything from ride height, to tire temps, to alignment, to damping settings explaining to me how to to get the most out of my xida clubsports once they become available. For me to get a even better understanding he provided me with several links so I can further my knowledge in the subject. So when you buy a product from 949 emilio tries not only to sell you a part, but make sure you understand how to use it to its full capability. This business moto and the excelent bang for buck punch that the clubsports pack is the reason why I plan to purchase them.