Don’t be an asshole about it please. “Doesn’t seem to know the value.” isn’t an excuse to rip anybody off. Since you said “She.” have you considered she’s a widow and that was her husbands car and she can’t part with it. Maybe no kids. So just offering some perspective that you can’t expect everybody to research everything and if she had no intention of parting with it she had no reason to consult anybody prior.
991 GT3 RS, not because I am biased but because I think while the Challenge cars are going to be more…visceral they’ll be also over the top and brutal for a “fun” experience. Especially for somebody who isn’t used to it. A 991 GT3 RS is plenty hardcore for 90% of people. So I measure differently I think. Most regular people (even people who enjoy cars) will leave a challenge car going “This is too loud, this is too hard, this is just unpleasant.” That’s a type of car you work/built up towards. My two cents at least.