Ahck! I'm getting my kits mixed up. These kits are generally good for 30 days and come with multiple nozzles so you don't have to worry too much about the foam drying and clogging the nozzles.
I can't say for sure but it does sound a bit high unless you were asking for Martha Stewarts...
R7 per inch sounds about right. There's a decent little project cost estimator on this site: http://www.sprayfoamdirect.com/spray_foam_buying_guide/
It's not cheap but even if you bought this and payed a contractor to install it I would think it'd be under $10k. Just beware that the product...
Sounds plausible, and a bit amusing. Something always could have snuck into their carb while you had the lid off the air filter and gotten trapped when you put it back on, but then it would've been crispy fried if you had turned the engine over since. But I'd be more inclined to agree with...