What is the difference between this variant and a vanilla SP-01?
Any Shadow variant has no firing pin block and a better hammer.
ShadowLines have some common parts upgrades over a non-Shadow, like an even better hammer (still not as good as CZC hammer), low profile safeties (I replaced mine with standard), a CZ-85 trigger, and maybe a couple of other things. My list is surely not exhaustive.
Of course, you could go look at the gun on the CZC website. I am sure the differences are outlined.