Let's start my "what car" discussion early.

I did a Viper track day once and mostly drove an '04 model. Except for the massive heat, it was sorta Miata-like in the way it drove. You'd swear they bought one and copied it. The controls were pretty heavy though, especially the shifter.

A friend has a first gen coupe, and it once needed a front cowl from coming lose in his enclosed trailer. I forget the exact cost, but it was something like $10k. Parts for the Viper are very expensive.

And I totally agree on the C5 Z06, they have to have the worst interior ever. I test drove a bunch a few years back before I bought my 370Z, and the interior is the reason I didn't buy one. I couldn't stand being inside them. They looked and smelled terrible. Drove nice however.

Keep in mind that all the cars you listed will not be cheap on tires. They all have big sticky rubber. My vote would be the Mustang. I got to drive a GT version, and as a former '08 GT owner, I was blown away. It's hard to believe they were from the same company. Even though it will be a limited use car, I'd rather be running than wrenching.

Several E92 M3's finished in the trophies at nationals this year. When set up properly, it is an excellent FS autocross car.

The Cayman isn't a great autocross car. The newer Ses are slower than the C6 and C5 Z06 in AS and the R is no competition for the Elise or C7 in SS. I honestly would get an S2000 CR before I'd get a Cayman.

I'm pondering these cars also. I think the z06 maybe just isn't my thing, but viper, v8m3, and cayman all intrigue. They're also really different cars. M3 seems like the winner for you given the kids and autox aspirations.

Bad assumption on the Corvette not being good in the winter.

Mine was brilliant. They have GM HVAC, the hydraulic limited slip works very well, the wide powerband and high power/weight ratio help in the snow, and corrosion protection on the mechanical parts is very good. I'm not sure whether the exterior body panels would've eventually rusted out but so long as you have a second set of wheels and tires or all-seasons it should not be in trouble until you have 4" of snow down and run out of ground clearance.

I drove a 3rd generation Viper at Skip Barber and was impressed with the car. I was expecting it to be absolutely brutal to drive, but I ended up really liking it. It's a very capable car, but also could be driven "normally."

I probably won't get the Porsche.

If I have either a Corvette or a Viper I would not drive it in winter if there was any sort of salt on the road. I have a truck.

My other thing is that buying a Corvette Z06 at $35k or a Viper at that price it seems like they hit the bottom of their depreciation cycle around there whereas the M3 is probably still descending. I do see they are good FS cars and the Corvette is a good AS car. Not sure about the Viper though I see they have won various classes at nationals over the years.

I think the only Vipers I would want in my price range are the 2nd generation ones. The 1st generation ones don't interest me and 3rd are too expensive. The only thing is that the 2nd gen ones I can afford are likely all convertibles. Not sure how that impacts doing track days.

Having full wife approval on a car definitely has its benefits, but I still wonder whether she will like the Viper. The thing is I think she already made up her mind about it based on looks and whatever issues there are she will overlook because of that.

People who have driven them are telling me that the Viper is brutal on the street and unless you get an 08 or later it's not competitive for autocross at all. Figured it would be something like that. Not sure I was seriously considering the car anyway, but that pretty much puts me back in Z06 land.