Same, i think £2k all in is too much.
My thoughts are to get the M3 diff put in. Someone posted previously in another thread that you'd have to change some other rear parts too?
Turbo Dynamics Hybrid Turbos, Wagner Intercooler, DPF Delete Pipe with Sports Cat, Ecotune custom map ~ 422bhp & 618ft.lbs
Ohlins R&T with custom Swift rears