[VTECaddict]

The first thing you need to do is figure out what part of the suspension or handling you feel is lacking and then try to address that problem with the proper upgrades instead of just wanting to throw parts at it for the sake of throwing parts at it.

If you feel the stock suspension is very good, why are you wanting to modify it? You will only upset what you feel is already a balanced setup.

A bigger front sway bar will increase tendency to understeer, which the stock E9x already tends to do at the limit.

As for LSD, an aftermarket one will be easier than retrofitting the M3 one. Again, it's only worth upgrading if you feel your car has a performance deficit that the LSD will fix.