[Engineer Ed]

For $15K, I agree a turnkey would be nearly impossible to find unless you got lucky and came across a sob story. Then again, I'd be weary about someone selling a turn key Cobra for $15K.
There would definetly be some issues with a Cobra at that price.

I know you said "no projects" but you can get yourself an FFR for that just over that price with a wrecked donor with roughly 100K miles or more.
To do it in the price you are talking would mean it would have to be a "stock" build using only the used donor parts.

To give you an example:
The FFR is $11,900
$700 delivery?
$1-2K for donor
Another $1-2K for odds and ends (you will want to replace worn parts, seals, clutch, etc..... Add more $$ for non-donor wheels and tires.
Now figure a few hundred for an inexpensive paint job (Done by yourself) including all the body work.
Now figure $$ for tax, title and registration.

Expect to spend closer to $18-20K for a simple but decent Cobra you will be happy with.

If you have questions, these guys on the forum will give you good info, dont hesitate to ask. We will be glad to help in any way we can.

As for the Miata, the two cars are nothing alike.
The Cobra is beyond words... The Miata is a grocery getter.
With a competent driver and some decent mods, the Miata will make a fun track car, but there is nothing like the brute power of the Cobra.
And the miata doesnt draw a crowd of gawkers.

Have fun and good luck,
Ed
President, Deep South Cobra Club