1) The only BMW net is the one you describe. One I've seen that goes across that looks pretty well made is a Toyota one. A friend with a Camry actually has 2 in his trunk. Just need a spare fastener hole of some sort in the trunk to attach to.
2) I believe Colgan has a half-bra of some kind.
3) I bought a black metal one at WalMart for $4.
4) the UGDO is about $130 from the discount dealers (Pacific, Circle) and takes about 5 mins with an x-acto to install. There are instructions all over the place. I would imagine a regular dealer will charge closer to list for the unit, charge for the different panel instead of cutting the stocker, and an hour of labor, so maybe $300.
2) I believe Colgan has a half-bra of some kind.
3) I bought a black metal one at WalMart for $4.
4) the UGDO is about $130 from the discount dealers (Pacific, Circle) and takes about 5 mins with an x-acto to install. There are instructions all over the place. I would imagine a regular dealer will charge closer to list for the unit, charge for the different panel instead of cutting the stocker, and an hour of labor, so maybe $300.