Should i be particularly concerned about missing caliper dust boots?
 

I mean... yes they're there for a reason. The brakes also work without them so... Their current lack really isn't hurting things "yet".

Can anyone motivate me to put new ones in?

What are your long term plans for brake mods? Any? Seems to me the lack of dust boot will kill the seal fairly quickly. Not sure it would be catastrophic brake failure but hey. Anything that impacts the ability to stop should be suspect in my book. It's a safety thing. Some kid runs out in front of your Z, you would want to depend on those breaks.

just call the dealer and get it over with

yah, not worth worrying. just get the part and install it.

Yes, you should be concerned. Over time, the piston/seal will get dirty and start to stick. You have enough hydraulic pressure that stopping will not be a problem (unless it gets real bad) but the brake will not fully release, causing premature wear. And the chance of a leak occurring goes way up. You can get by without the boots for a while but you'll eventually have to pay the piper.

dust boots are useless. if you see any track usage, they burn up within the first few laps of hard braking. i know mine have. google around and you'll find tons of threads on various car forums about these as well. the consensus is that its fine unless you're driving frequently in harsh conditions (snow/mud/salt)

Whoa Sir, would you dip into the unknown waters without rubber?

You can get the rebuild kit from rock auto for $5.