Any T4 based charger will be a drop in as your s300 sxe is T4 also. So take your pick. Garrett make nice ball bearing chargers, big $$$$$ . As does precision, also big bucks.
It will never be a true drop in though as the 4.21 marmon flanges the box s300 have are not to common on other chargers. There for you'll need to adapt or change flanges on your down pipe.
The rest of it are perty much the same . Work turbochargers in Alabama make a nice s300 based ball bearing charger that would be a true drop in. Like others have mentioned , that would be lots $$$