Shop4parts show 5W-40 for the earlier engines and 5w-30 for newer ones. They show 5w-30 for the 2009 EVO. I like an oil which circulates quickly when cold and both oils are a 5 viscosity when cold which will be good in this repect. With the kms you quote above on the clock I'd be very happy to stay with the slightly thicker 40 hot rated viscosity.
I like to change engine oil yearly or with no more than 10,000 miles since the last change - don't believe in extended intervals at all! My favourite oil brand is Fuchs. Only one of our family cars does over the 10,000 so they all get a yearly oil change but my boy's Astra - his work vehicle which clocks up the miles - gets it's oil changed every 6 months and it's at considerably under the 10,000 at that time. Wasteful? maybe. But I really don't see any engine wear problems and apart from my Ibiza and my older boy's Kia the rest are all old - 2007, 2008, 2010 and 2012. The Astra is now getting towards 150,000 miles and doesn't burn a drop of oil!
I'm not at all in favour of engine flush additives. Change the oil regularly and don't subject the car to frequent short journeys where it never gets properly hot and you'll have no sludge problems. If I come across an engine which is a bit sludged up inside I just double up on the oil changes, that way the sludge is dissolved slowly by the detergent in the oil and mixes with the oil rather than using a strongly detergent product which may break away solid particles which may circulate through the engine and cause all manor of problems.
In my opinion engines with chain driven timing gear benefit greatly from having fresh clean oil. I've said above I don't believe in extended interval oil changes and even if the manufacturer Ok'd a 2 year/20,000 mile (say) interval on one, I'd never do extended interval oil changes on a chain cam engine.