Hi Rich,
The sheen in paint increases from flat, satin, semi-gloss, and gloss. As you go up the sheen scale, there is more resin in the paint which makes it more durable.... e.g. That's why semi-gloss is recommended for a bathroom. Satin is different than semi-gloss.
Here is the sheen that I used. I basically replaced what I saw:
-Radiator support brackets - satin
-The brace in the engine compartment that has a body bolt on each end - didn't paint but it appears to be satin
-LCA's -gloss
-UCA's- gloss
-Stabilizer bar/Sway bar - satin
-Impact absorber (paging Rob) - gloss engine enamel per Rob.
-Steering rack tube & tie-rods - satin
Cheers,