And now for my .02 cents.
Being a prop builder of sorts (I have an R2 unit my son and I built, some from scratch, some from R2 Builder club parts runs), I'd say just go for it and see what happens. I did a model of the Wormhole emitter last year that's on Thingiverse, which is free, and pretty accurate to photos and measurements of the actual one that Gary Weaver posted. Is it perfectly accurate? Probably not. But it's close.
I made it because certain people sell a resin cast version for $500 bucks, which to me is kind of grand larceny. But then they probably sell them for that because some people are willing to pay that much. I'm not, and I can make 3D models all day of parts and then put them somewhere where anyone who wants to save a buck can either print them or send them to get printed. The days are much different than 8 years ago when I built my R2 and had to wait for parts to be made in a run - though those were still reasonably priced due to the R2 Builders license and agreement with LFL. As I have time I'll be making more external parts (Mr. Fusion that looks a bit more accurate than what's online now from other makers for instance) to share as well.
Having said that, it's interesting how many people think my modded DeLorean is the one from the movie (it has a spoiler). And then I've had comments from people with very nice cars (like Lamborghini's and Ferrari's) comment how much nicer the stock (though it's not) look is to the time machine they may have recently seen.
I do have stuff inside, like the Flux Capacitor (which gives everyone a thrill and they all have to get a photo of it), Doc's glasses, the speedo, and a HoverBoard. I wold like to have vents I could just put on and take off that fold up nicely, and I do stick my top part of my actual Mr. Fusion (a Krups grinder) to my louvers with a little bit of Commando 3M tape, and it lights up too. I would like to have a light up static version of the time display circuits I can just set or hang from the dash in front of the vents when at shows or events, as I get a lot of requests for those with the car and me as Doc Brown.
So if you plan on it, I'd have a better version of the Wormhole emitter than you have now on your car, as well as the Mr. Fusion. Your flux bands look pretty spot on though! And if you could have interior parts that look the part but are non-functional (the time circuits in the movie were just gels), then you might have something there.