Todd, I'm not sure if this will help with your situation, but here's how I look at it:
First and foremost (and obviously), if you might get yourself into financial trouble, don't get the Perf. The standard is way more than adequate (I really enjoyed driving it, despite being used to the Roadster), and the Perf, while fun, is clearly not worth losing your house, skipping meals, not taking your kid to the doctor, etc. You will hate the Perf, and family members will hate you, if you are ever in any of those situations. Only even think about the Perf if you are positive you can afford it. (And whether you can afford it depends on spending as much as income, so I can't tell you if you can afford it or not). If you aren't sure whether you have enough or not...don't risk it.
But if you are sure you have the money--go for it. Sure, you will agonize before you spend the money, because it's ridiculous. (A few years ago I was in a similar situation; the Roadster was the first car I bought that topped $20k--and boy did I agonize). Sure, you will get a sinking feeling in your stomach for a few days after you hand over the money (the Roadster was more than my first house! Well, not after inflation, but it's still a huge psychological barrier). But a few days later, when the money bit is all history and you're driving the car--you will be happy to have the Perf every time you press the GO pedal. Especially when you are taking EV doubters for a ride. Once you have the Perf, as long as there are no financial repercussions, you will never regret having it. It's not like a gas car, where the performance version has disadvantages, like lower fuel economy. The Roadster was a huge departure for me, but I don't regret it a bit.
That said, no rule is hard and fast--I can afford the Perf but bought the standard. But it will be my wife's car, and she doesn't care. (I still wonder if I should have gotten the Perf anyway; I know I will be taking people for rides...)