the only required mods for stage 2+ are the performance downpipe(with sports cat or decat) and the uprated HPFP.
reccomended would be the intake and intercooler.
garnishing would be the likes of the cat back exhaust (for noise), intercooler charge/ turbo discharge pipes.
i ran mine on intake/hpfp and downpipe and it was very very good. however i logged mine n numerous occasions and the std intercooler really struggles to cope. IATs were through the roof after 1 big pull through the gears and took forever to recover