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you dont really need pressure at revs but when boosted you need as much pressure as you can get at low revs.this is why the v6 is so hearty and does so many km untouched they have very tight bearing clearances to handle high torque loads at low rpm.unlike a chev thats got loose tolerances to allow higher revs.if you setup a v6 with chev clearances it wouldnt last long same as when you rev a v6 they dont tend to last long before killing bearings

thats why higher pressure and thinner oil help a lot on these v6 when u rev them a lot.

Thats why VY and VX engines are able to handles constant revving and thrashing with long engine life.

They specify a thin oil, something like 5w or 10w I think VT and VS still specify a higher grade.
I also speculate VY and maybe VX have stiffer/longer spring again. I could be wrong on that though.

When looking at oils the first number is the cold start rating and the 2nd number the oil viscosity at operating temp i.e a 15w-40 is a slightly thinner oil than the standard 20w-50 which is the recommended oil for the ecotec and the 15w-40 is recommended for colder envirnoments.

20W 50 is crazy thick, I have had best results with 10w and 15w50 in summer.

20W 50 is more suited for around town mum and dad drivers, not lead footed drivers like us lol.
Even the US counterparts use as thin as 5W 40 in the later generation 3800, circa VX-VY for us.

My friend ran 5w 40 in his VY, that car was constantly red lined coz of the lazy shift kit he installed.

bearings were nearly perfect, only slight main tunnel misalignment issue, 350k that did and not one bit of oil starvation was evident. The bearing could of easily doubled the ks that they did.

Anyway just been at Holden after work, got all the part numbers for the springs. VP-VY are all the same, VN was different.

I am going to pull some springs out of some ecotec engines soon to confirm this.