Help... 90 Monster Miata built by Martin value
 

Need your insight. Found actual 1990 Monster built by Martin's team. Has 19k miles as monster with second engine being from Summit with GT40 heads.

Car was shipped to Monster as a flood damaged and of course has new drivetrain from Martin.

Needs tires from age and the FAST EFI will not idle (dies). What is it worth? I see the flood damage following me and impacting resale.

Im at 18,500 and he is at 21k. Stock suspension and brakes other than drilled rotors

Hard to say without photos of overall condition showing exterior, interior, engine bay.
If it's on its 2nd engine at 19K miles it might have had some hard use or lack of care.
Got a hardtop or just the convertible top?
Air conditioned?
Tire & wheel widths? Flared fenders? Louvered hood? Monster hood scoop? Roll bar?
And of course a car is worth whatever someone's willing to pay for it...