Since you said KM I'm going to assuming you're Canadian like me, and have to deal with our amazingly awesome road salting. What I did was get the yearly under coating from Ziebart.
Also, every 60,000 - 70,000km I change my spark plugs, fuel filter and transmission fluid (manual transmission). Also, rather than the 5,000km oil changes, I use synthetic oil and change it every 3,500km - 4,000km. Excessive...yup. Does my car have engine noise...NOPE. I swear my engine cleans the oil. I also don't use aftermarket filters. GM filters are like $8 each, and if you plan on doing them yourself, buy several at once so you don't keep putting off your oil change since you don't have a filter. I usually buy 5 or 6 at a time since both me and my fiancee have the EcoTec engine. I have a cold air intake, and try to at least blow it out on a regular basis.
Also, like others have said, any issues, take care of them immediately. I had my intermediate steering shaft seize up, it was changed within 36 hours of me noticing anything. Also, my control arm bushing let go, that was changed the next day.
Also, some people may overlook this, but your cabin air filter should be changed regularily. You never know what can get stuck in there, whether it be leaves or a mouse. Also, when you change it, either reach your hand into the fan and make sure there's no debris or take the fan out to make sure. An out of balance fan can end up costing you some money.