Hate to say it but you may change your mind when you try to sell. Our C-4's are as many have said over and over, worthless (if you have any money into them to begin with) for resale. Corvettes (as with any collector car) all will have the low point in there value. My father is a HUGE 56 chevy nut, he has lot of 55, 56 and 57 cars. We used to get every one we cold back in the 80's and I would say we have 30-50 cars. Most are parts cars, 4 doors etc.. but alot of the cars we got back then and assumed would be "parts" cars are now cars people want to restore (even the 4-doors!). His pride is a 56 convert that he got for like 3 grand.. you couldnt buy it now for 15 grand....
Point is, if you really want to sell, now isnt the time. our C-4's are at an all time low unless they are super low mileage or prestine. But unless something really goes wonky, the price will start to climb and the value will be back in a few years. but right now they are almost free. I bought My first vette 2 years ago... after 20+ years of dreaming I found one that was what i considered CHEAP. Well I was wrong. I have put maybe $3000 into it in 2 years and today I would be lucky if i could get what I paid for it (by e-bay and other cars i have seen for sale (that actually sell)).
regret? some, I love the car, love to drive it and am actually getting it out of garage today for first time since it went in before winter. Still to wet to relly drive it. But I know if i could do it over I would have spent more money for a better one (still probebly bought a C-4, but a newer one) and looked harder. But hindsite is 20-20.. Love the car, do not reget a vette, and only slightly regret the one i did buy.. never when I'm driving it.. but somtimes when i see a cheap better one, or when i buy a new part..
hang onto it unless you somehow get what you want (good luck). it will gain its value again, but only with time.