Ideally, I can make anything with 120+ work, but it’s dependent on weight, and what I’ve found in a modern car that weighs two tons is about 520. Hear me out, feel free to judge me anyway.
1. I am forced to drive on lots of small tight roads with small passing areas and dramatically slow people keen on taking in the sights. We are talking sometimes more than 10 under the limit with no enforcement, delaying for over half an hour over the duration of about 25 miles.
2. These slow people are often petty, taking their mustangs and such and accelerating them if someone tries to pass.
3. The strategy that has worked for the least amount of risk to everyone is to accelerate to passing speed before anyone has a chance to do anything else about it, and then come back to regular speed as soon as reasonably possible.
4. I carry a “I’m sorry” electronic sign for unreasonably angry reactions.
5. On the Interstate, of which is dozens of miles away from home, I do flow of traffic.
6. 1-3 need about 450 hp, so the 520 is for good measure, and of course you need brakes and setup to slow down appropriately. All I want is the burst of speed necessary to make it without allowing other people to risk that activity. You can say I should just stay behind them, and 85% of the time, I do, since I only pass when it is absolutely clear and I don’t muck with double lanes.
But I have encountered enough sports cars with 300 hp or so trying to make my life difficult by blocking intentionally, or literally driving between lanes, and I want to be able to be in front of that, instead of being exposed to more danger behind that.
Accelerating on extremely short onramps into 80 mph traffic also comes into play, but is a separate situation entirely.