Given that there is a lawsuit over the fact that literally their track packs suck...the GT350 prices will suffer sooner. Folks are fickle...just read the replies around this subject in our small section. If you want a higher volume 17-1LE go for it, in two to three years it will be worth 28,000-35,000 dependent on condition. Same thing on a ZL1-1LE - except it'll be at 40,000+. Unlimited production makes neither particularly collectible.
A 14 or 15 Z/28 is going to find a bottom end valuation spot. Personally I'm betting we see the sum of the parts as worth more, but a average value for a low volume Z/28 seems to be 43 to 45K; just like my 09 Z06. But the 14 or 15 Z/28 -> LS7,TR6060, 3.90 differential, and ceramic brakes -> limited serial numbers...
Maybe its just me, but I remember all too clearly a friend of my family from my youth who lived right behind us. He was a mechanic at Graff Chevy in Grand Prairie Tx, and I cleaned his '67 with a 427 tri-power every week when I was in the 8th and 9th grade. I also cleaned the 69 L88 427 tri-power he traded that car in on as a teenager. I didn't earn much, but I had the joy of taking care of two beautiful cars. I remember him telling me about engine, telling me it was something special. I often wonder if he had the sense to keep that car..considering they can be worth >$500K. I had the chance to ride with my neighbor in that L88, and it was seriously fast for its day; it left me with a hankering for a 427 for life.
Then lo and behold, an idiot driver in Tulsa totals my 11 LS99 2SSRS - which we'd still be driving except a 23 year old without license or insurance ran a stop sign..(YES!!!!), and I re-cooped every dime I paid for that car plus $2100 in inflation -> and pulled the trigger on my '15 Z/28. It made my 2nd LS7...it was like it was meant to be. So you'll be catching me here for years; as I don't know if my neighbor kept that 69 L88 - but I know I'm keeping mine.
Who knows perhaps time will prove the car a collectible and I'll have had a chance to own a car that made my blood boil..and lots of others based on all the comments I hear. That doesn't happen too often either.