LA257 front CVDs are the same as are LA272 f/r arms and I think the rear CVDs are the same too (#UM510 on ZX6, I think these are also the same as some versions of the RB5). Wheels are identical and i'm pretty sure the slipper/spur assembly is the same.
ZX6 front hubs are different but the LA254 hubs will fit.
Also the shocks are the same to my knowledge with the exception that the ZX6 is supplied with 2-hole pistons as standard but I never had an FS2 SP, it may be the case that they were stock on that car too.
I adapted a ZX5 SP2008 shell to fit mine (#LAB03), it's similar to the FS2 shell but slightly shorter. It's my winter shell as it's more enclosed around the rear of the car so water and mud can't get at your electrics.
TBH one of the reasons I bought the ZX6 was parts compatibility with the ZX5, I think it's great that so many things carried over as I had a load of SP2008 spares for a car that was no longer competitive so although the ZX6 is strong money, it's cost me less than buying a cheaper kit and starting all over again with spares, wheels etc.
