Average car: Unless the MSC has an instruction about your vehicle, I would not worry about it. Even very "average" folks will go out to very nice meals every once in a while, such as for special occasions.
Valet Tip: Check the restaurant's policies. There are some upscale restaurants in my area that have policies that do not permit the valets to accept cash tips at all. They are a part of the restaurant's overall service team and get a cut from what gratuities left at the table. Otherwise, $3 is generally reasonable. You offer the tip when you retrieve the vehicle.
I don't drink much either and will generally order the very minimum for required alcohol purchases. When possible, I prefer a beer - but will pay a couple bucks extra for something good.
You'll likely get better advice from others on this question.....
Regarding budget: The compensation for some of these nice restaurants is more of a huge discount than anything. It is sometimes difficult to stay under the reimbursement amounts and/or shop fees. I think most folks take them so as to make a very nice meal out affordable as opposed to a way to make a profit. My wife and I will shop one such place about once every two or three months. I typically spend just over $100, but the compensation is only $75. I do it because we love the food (it's one of the best seafood places in the Seattle area) and the required timings and other details are not particularly onerous, allowing us to really enjoy the meal. In other words: it's fine dinning for the price of Chipotle.
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