Will a full spare tire fit where the space saver tire fits.

If it ALMOST fits, and if you REALLY want to carry a full size spare, there is another option: Partially deflate the full size spare (until it fits), and carry a 12V inflator. This isn't for everyone, it definitely adds a layer of complexity, and you'd want to be sure that anyone who drives your car is aware of it. Maybe even put a big label on the spare that it requires inflation before use. But this is admittedly preparing for an unlikely situation - I agree with you that anyone with ANY spare is way ahead of those with no spare.
But I've been in situations when a full size spare really saves the day (or days) - when you can swap it out and continue your trip, rather than finding the next tire shop that's open, being stranded in a spot with no cell phone reception, possibly spending an unplanned night somewhere until a tire shop opens, etc.
I like to carry a 12V pump & repair kit regardless of what kind of spare I have - if you get a "simple" flat (like a nail in the tread, not a sidewall split), I find it quicker and easier to patch & re-inflate than to completely remove and swap a wheel. IME the rope-type patches can last multiple seasons, possibly the life of the tire.

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Honestly what I do is just carry a container of that Fix-a-flat in the storage bin. Unless you've got some kind if nasty sidewall tear or something it's usually enough to get you to a gas station to put more air in and deal with the flat later. It's expensive and It's worked for me many times.

 

does it have any effect on the tpms?