Was looking at caliper/rotor combos by stoptech, brembo, and wilwood.
Their prices vary wildly.
Brembos I know are renowned, but is the $3451 price tag justified?

What kind of performance increase can I expect?

I want a car that can be tracked, raced at the quartermile, but I can also take a nice girl out on a date in too, so of course I need a decent interior and A/C.
And I was thinking a brake upgrade is usually good, especially prior to picking your wheel sizes and offsets.

Then there's the matter of the brake pads. IIRC you can upgrade the pads in a matter that increases their thermal efficiency before getting too overheated, without destroying their street ability, but a pure racing brake pad would compromise street ability, and the brakes would perform very subpar for matters of street driving, as the brakes would never heat up enough to reach their proper temperature for performing effectively, may also include needless excessive brake dust and wear and tear on the rotors.

What's the consensus on here about slotted and crossdrilled rotors?