Went and looked at a '95, when i put my toes up against the passenger side sill, where they normally rot, a section that was maybe 6"x10" fell off. Behind was lots more rot. Needs a battery. Has a decent interior, new tires (pedestrian, black and round), hard top and PEP (so Torsen). I know that the answer is "Exocet", but I have a Miata for that already. is the answer "buy it, and sell it to someone building an Exocet? With unlimited storage space, it would already be mine, but alas, we can't all be Steve :P
Well, at first as I'm reading I'm thinking "no, nope, no way, no how". Then you said hardtop, and I thought "maybe." I guess it depends on the price. It seems like a decent partout car since you have a hardtop, powertrain, torsen, and premium interior to part out. Realistically, I wouldn't touch a rusty Miata if you are planning to drive it, though.
I've been the rusty route myself. I got the car at a really good price. It had a very solid interior and low miles. The rust wasn't as bad as what you are describing. I got both the rust repairs and the necessary repaint done at a really good price. When it was all said and done, though, I probably could have purchased an equivalent "clean" Miata for what I put into it. Any honest shop is going to tell you they can't guarantee rust repairs, and there's a good reason for that. If you can do the work yourself, I suppose the economics tilt a little more towards a car like that, but not much. If I had it to do over again, I'd shop longer, spend a little bit more, and not have to wonder when/if the repairs are going to fail.
EDIT: I suspect if the sills are rusted through, the underside of the car will be a nightmare. Only root canals and interior home painting are less fun than fighting with a rusty undercarriage.
Do it. I's not like you were planning on keeping it forever, right?
Hardtop: $700-1000 depending on location and condition.
Torsen setup: $800-1100 depending on miles.
+ the rest.
I'd say grab it if you can part it out and make money based on the above prices.
For a car as common and pedestrian as a Miata, I don't see the point in starting with a rusty example.
mistanfo wrote:
Went and looked at a '95, when i put my toes up against the passenger side sill, where they normally rot, a section that was maybe 6"x10" fell off. Behind was lots more rot.
That's all I needed to hear.
Sell it to someone who wants an Exocet / Catfish / Miata-based Locost donor.
Update: Leaving work in less than an hour, buying for $500. Yes, $500, OEM hardtop, Torsen, approx 134,000 on the odometer. I'm even considering driving it to VIR this weekend. I'll try to get some pics, and am happy that I got another inexpensive Miata (never gotten this good a deal).
$500 is a pretty good deal. My rusty Miata was a lot more than that, and had other problems on top. Made a helluva winter beater though.
Wow. I still say flip it/part it, but the hardtop alone is worth more than $500.
And so the myth of the "almost free Miata" is perpetuated. 
Given that it's got a hardtop AND a Torsen, paying $500 for it is like being paid $1000 to drive a Miata around for a couple years until it starts to fold in half.
And that's if you sell the hardtop and rearend and then just sort of walk away from the rest of the car instead of putting a regular diff in it and selling it to someone else for $1500, which someone WILL pay that much money for it...
