I currently own a 1973 Corvette convertible that I am restoring. I think you will find many similarities between the Crossfire and the Corvette! Regarding the car's value, check out Hagerty Insurance's valuation tools - i find them to be fairly realistic, since they offer these tools to help customers appraise their cars for insurance purposes.

According to Hagerty, a base model (L48) 1972 Corvette Coupe (hardtop) in good condition (Condition #3 using their categories) could be worth $18,400 in the current market. The Condition #4 cars are valued at $11,800. So figure anywhere between $11,80 and $18,400 - and it seems like you are already in the sweet spot between the two.

I have no relationship with Hagerty (I am not a customer of theirs) but I do have an interest in early '70's corvettes, owning one myself. So good luck on your decision!!