Degree of stiffness (minimal weight difference). S200 and Project X 5.0 would be same stiffness (R+). S300 and Project X 5.5 would be same stiffness (S). The DG is 12g heavier - theoretically a .5 swingweight point difference. The Project X may have a thinner butt end, so that may equalize swingweight (it is the same weight as a TT Lite XL but the PX is a low trajectory club and TT Lite XL is mid trajectory). You may get more feedback from the PX, assuming it has a lighter butt end - I base this on TT Lite XL vs DG (personal experience). Can't speak with authority on PX - only on data. The other difference is price - the PX is $38 per shaft and the DG is $15 (Golfsmith prices).