Thinking about using some SEM Trim Black for the side valence, spoiler and rear valence. Prbably use it single stage with out clear coat as it has a satin finish. Is there a satin clear coat available? My paint supply shop said only glossy clear.
Have heard of using lacquer thinner in place of reducer will yield a satin/semigloss finish(?) with some paints, but I wonder about the effect on clear coat.

I would just use a satin or flat black paint from a spray can, those parts get rock beaten pretty good and it's easy to touch up with a rattle can and fast. No muss, no fuss.

wurth satin spray paint? What about paint for the actual bumpers?

I've been using just regular Rustolium satin and it looks good. I hear Wurth is better.

There are a lot of satin paint on the market and satin clears too. I know that the clears are quite fragile and are not the thing to use for lower parts of a car. House of Kolor has a flateming agent that can be used too. The satin paints are designed for the hot rod crowd and I've seen them advertised in many paint mags. I'll try to get some names if you want to go that route.

I use the SEM trim for everything. bumper tops, hard top, door seals, etc..matches great and looks good...

Whoever told you using laquer thinner will yield a semi-gloss finish has been drinking too much laquer thinner ! YES there is a semi gloss clear.I have used it quite a few times repairing mid-late 90's Mercedes bumpers. Next time you're next to one look at the bumper cover. In addition to buying semi gloss clear, you can also buy a flattening agent and add that to regular clear. That is in fact all you get when you buy the semi gloss in a can, and you pay a little extra for it

I am going to paint my GT front valance the body color and will try this product on it.
If I was going to paint it Black I would probably choose a Wurth product and use their chip guard.

http://armorcoat.armorauto.com/