"It depends."
First, this car, which is a fine example in good condition. I'd love to put a ZR-1 in my garage and if I had the scratch, this would be a very tempting car. Of the C4 ZR-1s, the most prized are 93-95s due to their improved cylinder heads, and of those, 94-95s have a much more refined interior. Throw in that black rose is a comparatively less common color and that the car is clearly well kept, as a car to cherish and enjoy you would probably see minimal depreciation over the mid-term and an opportunity for modest appreciation over the longer-term.
Keep in mind that this is unlikely to ever be anything other than a "3" car. The nice thing about a "3" is you can actually use it. Go ahead, dive it on pretty Saturday afternoons. Use it for club activities. Put it in a local show if you like. Exercise it. Won't cost you nothing, as the saying goes. Enjoy its "tasteful" mods (I really dislike that expression, honest). You say the seller scrapped the original rear gearset or misplaced the original chip? Laugh. You don't care about originality or future NCRS flights or Bloomington awards because it's just so good on the road.
But a Corvette is not a blue-chip investment car in the way that the Italians, some Porsches, etc. are. Sure, a Corvette can appreciate. Have you followed mid-year prices? They ain't cheap. Unless it's an unusual color or a combination I haven't seen before, even a superb midyear doesn't even turn my head because I don't hope to own one (too young to be sentimental about them since their day was well past when I was growing up, and too poor to compete with well-heeled boomer retirees who always wanted one). They're timelessly beautiful, just not for me.
And only the most special Corvettes, with specific pedigrees, really compete with the iconic Europeans for price appreciation. Because of that, they aren't the investment-grade choice for people who can afford such dalliances. When my B2k was lowered from the transporter, what was underneath it with a plastic cover to prevent its being soiled with even a drop of synthetic from a weepy turbo line? A Porsche 918. The buyer purchased it solely as an investment. (I'll load pics sometime, it was pretty neat). The few miles it was driven on the autobahn (European delivery) before being shipped here in an airplane are probably more than it will ever accrue again.
So, a nice ZR-1 as something to enjoy that might hold its value or bring you a little something over time? Go for it. They're great to drive and way easier over long hauls than a C5 Z06. But as investment? Well, it's a great Corvette. 
Edit: Wanted to add that the only C4 with real appreciation potential in the near or mid term is a 88 or 89 Corvette Challenge car, and their prices vary according to who drove it and how it finished. Prices for these have already started climbing. Sure wish I could have afforded one when I was a younger man. At this point, they're becoming lotto-mobiles unless my earning power increases significantly.
