I expect the MR Vette with the V8 to sit significantly above the price of the FR V8, say in the £100k bracket, with the MR V6 to sit where the current model does. If so, expect residuals of the FR V8 to remain very firm, as who wants a V6 Corvette??
With Brexit still to hit as well, I think any guesses at values in 1-2 years are pie in the sky right now. Depending on your ’contract’ with Nissan, if Nismo values hold you can probably get out anytime you like tbh.
I’d say the C7 is already an utter bargain, if you can live with LHD.