what will fit my hawkeye wagon NA

Hi all, got myself a 2006 hawkeye wagon (GG) 2.0R non turbo just over a week ago. I want to change the suspension and maybe the exhaust. my reasons are that 1 rear shock is knocking and the whole car sits too high for my liking and is a bit sloppy. I want to pick your brains on what is compatable to fit my car? will saloon car shocks and springs fit with no modification? will WRX suspension fit (wagon or saloon), looking at opions on used and new. Will a good set of used WRX struts fit?? same question with the exhaust. i want to improve the exhaust not to hear a bit of the boxer burble. Will saloon performance centre and back box fit or have I got to get both for a non turbo 2.0R wagon. Any help or even anyone selling any of these items that fit my car would be greatfully appreciated.