Concening parts, you need a shim kit and anything else i have no idea about. Check M3F for valve adjustment threads, there is heaps of info on the subject.
If you don't do it? I am unsure what the side effects are apart from the ticking noise. Given that your car only has 90,000km you have a couple of years before you'd need to do anything imo.
2006 CS M3 | ESS Tune : CSL SMG tune : Eisenmann Race : Eibach : Tekarbon