I'd highly recommend doing what I'm doing. Don't use street pads on the track, and don't use track pads on the street.
Agree 100%... to get the most out of your brakes you need to use the right products, as they were designed to be used.
Yes, it'll require you changing pads/rotors before and after an event. But, you won't have to do it at the track. You can do it the night before, or even a few nights before.
Unfortunately I have no way to change pads/rotors anywhere other than at a track. No space in a garage or driveway (unless I borrow one from someone every time), and I have to drive my car the next day to work. So the only option is to swap everything at the track or run a street/track pad (understanding and staying within the limits that it creates).
If you use street pads on the track, they'll be fine for the first 1-2 laps. Then, you will get used to the track and start driving the car really hard. But, your brakes will now be hot, and when you go into that critical "Turn 1" (or whatever turn is after a long straight), you will hit the brakes and they won't be there because they've overheated. You'll have no brakes, and you'll have an OTE (Off-Track Excursion).
If you use race pads on the street, you won't ever get enough heat in them to be effective. You'll be driving along, brakes nice and cool, and have to make an emergency stop, and your brakes won't stop you effectively.
With my setup I've found that my tires are the weak point both on the street and track. At the track my tires get hot and "greasy" before I notice any fade in the brakes... my pace at that point is limited by grip and the speed I can maintain through the corner, requiring additional braking (or just backing-off a bit on the straights). On the street, even with cold pads and "emergency stops" from highway speeds, the initial bite form the HP+ is more than enough to lockup wheels (and/or engage ABS).
Then again, I wouldn't consider the HP+ a "race" pad... I agree fully that running a race pad on the street is not a good idea (and not just because of the rotor wear, dust, or noise).
Brake pads are only one of the many reasons why I've decided that if I want to get into track days seriously I need another car. Going much beyond where I am now pushes me over the edge where I can't effectively daily drive the car. It's a slippery slope... adding wider/stickier tires means I'll need race pads as with more grip I'd definitely cook the HP+ pads. I already feel the need for a race seat/harness, and that would only be exaggerated by more grip... but to do that properly would mean adding a cage, and that's just not something I can live with in my daily driver. I also have additional concerns about oiling, chassis flex, etc...
In the end, I like the setup I'm using now... it's not going to set any lap records, but it works well as a daily driver and weekend fun car that sees the occasional track use.