318is engine

[swansea v6]

Have just picked up a 1998 compact 318is, which has the 1.9 twin cam 16v engine. Having never owned a 4 pot bmw before are there any 'essential' mods that I can do to it? Am planning on changing coolant, thermostat, engine oil, gearbox oil and plugs next weekend and either changing air filter, or fitting induction kit. Are there any free breathing exhausts which aren't too chavy sounding available for this engine???