I am becoming captivated with the Spirit frame.
I have been researching more about this frame and have started communications with Lexon. It appears that the Scott Spark has a head tube angle of 66.5 degrees, with ZS56/28.6/40.0 Integrated cable headset cups. One can install zero offset cups or keep the cups that allow one to rotate them for a either a HT angle of 65.8 or 67.2.
Head tube differences:
The Spirit has a fixed HT angle of 67.2 degrees that uses a IS52/IS52 integrated cable Headset.
The Spark uses what appears to be a custom Acros angle headset:
https://acros-components.com/en/headsets/angle-headset-1-52/52?number=310.52.591F-HT110AM&c=46(These headsets have protruding pins in them that allow them to be flipped 180 degrees. The Scott Spark has little notches machined into the Head tube portion of the frame to clock/orient the cups and hold them in place.)
I asked Lexon if their Spirit has this feature/provision, and if not, can they add the grooves.
Rear shock differences.
I believe it is known that the Scott Spark uses 2 versions of custom Nude5 shocks with a mid position set point. The Spirit uses either the Rockshox Deluxe Selected+, or Rockshox Deluxe RLC3 with remote. Both of these shocks have their air fill port located coming out the side of the end of the shock. This makes one have to remove the shock in order to add air/adjust the pressure. (Not fun to do if you are out in the field.)
Frame differences.
Scott uses a BB92 bottom bracket and the Spirit uses a BSA73.
There are some very slight differences in the front section of the frame geometries, resulting in slight wheelbase differences. Scott Large = 1190, lexon Large = 1181.
I can't predict if these small difference would affect handling or the ride. I suspect the Spirit using T800/T1000 fibers would have more of an impact versus Scott's use of carbon nanotube reinforced epoxy resin and T1000G fiber.