oil viscosity for older vehicles

[barks]

hi,
without trying to start an over discussed issue,

2002 03 model boxster 2.7 124k miles, i live in uk, -12 to +34

this car is recommended by porsche to use mobil1 0w40 but its now 13 years old and done 124k miles, does this change things??

my car sounds fine untill it reaches about 60 degrees then there is a noise on deceleration and idle, as soon as i rev past 1500 it stops.

the noise is never there when its under 60 degress when the oil is thicker so,,

does the engine just need thicker oil when hot due to engine wear?

what is the ideal viscosity for the variocam?

i think if i use 0w 60 it would stay quiet but obviously not flow as fast round the engine so would this cause the oil to overheat thus loose its viscosity and be pointless?

has anyone ducted cool air to the oil cooler?

yes ive read loads of articles, everyone has different opinions on oil, yes i know there isnt a 0w60

looking at castrol edge titanium 10w 60 or mobil 1 peak life 5w 50 ?

cheers
barks