Honda recommends dino 10W30 for S2000 since 1999, few years later Honda recommends 5W40 for cold climate and 10W30 for warmer climate. These recommendation were valid until they stopped producing S2000 in 2008-2009.
I think the reason 10W30 was recommended for S2000 because it was more shear stable than dino 5W30 14-15 years ago when they test it. Modern dino 5W30 SM/SN is fairly shear stable, no need to use 10W30.
When I do the next oil change I'll use a mix of M1 0W20 and 0W40 in the ratio of 3:2.
I think the reason 10W30 was recommended for S2000 because it was more shear stable than dino 5W30 14-15 years ago when they test it. Modern dino 5W30 SM/SN is fairly shear stable, no need to use 10W30.
When I do the next oil change I'll use a mix of M1 0W20 and 0W40 in the ratio of 3:2.