One thing I wanted to add about engine oil additives is that Honda says, they ship their new cars with a special oil.
The oil they use is really not that special, it contains a high content of molybdenum.
Moly is an additive package used to help further the process of curing metal.
The Moly reacts with the metal parts that are not fully hardened and cures them faster and stronger.
I used a Moly additive in my S2000 engine for 10,000 miles, and several other sports cars. The result was always an engine that was stronger.
And I have dyno numbers to prove it.
Technically, using Moly after the first 10k miles does nothing after the metal is fully cured, however many oil makers, like Castrol, Mobil, Redline, still have moly additives in their oils, mainly because of the protective film it leaves behind clinging on parts even in hot or cold temperatures.
The use of additives are also effective for long term storage.
Moly additive in these situations can further reduce, gouging and scouring.
Some on more expensive sports car will actually spray a bit down the cyl. walls and hand crank before starting after a long period of storage.
So to make a blanket statement that additives are NOT recommended is innaccurate.
In the case of the Insight however, as a daily driver, the additive packages of conventional motor oils are more than enough to protect.