I have StopTech 2 piece rotors that I run on my SRT. I have gone through 2 set of drilled rotors and 2 sets of slotted rotors. I started out wit the drilled ones mainly because they dissipate heat and gases the better than slotted. (basic physics, not opinion). The problem is that they are more prone to cracking, any time there is a hole, stress builds around the perimeter (more physics). They work great and look very cool. It is basically a matter of intended use.
Brand new drilled rotors after a 3 day track event (front wheels) were cracked everywhere, brand new slotted rotors after 3 day event cracked a quarter as much, I had pictures but I could not find them..
My drilled rotors cooled faster than the slotted ones, more surface area, more air flow, physics again. Not hard to understand that the faster cooling/heating around stress areas equals more cracks. I get 4 times the use from the slotted ones as I do the drilled ones. I don’t toss rotors for wear, just for cracking.
If I had the budget, I would run drilled all the time and just change them after every track event. The StopTech’s aren’t cheap so I use the slotted. My experience has been at the track where I brake extremely hard. I run slicks and a very aggressive race pad, so I can really stand on the brakes. With street tires and street pads you would not see it as bad or as quick. If you are just ripping around the streets then I can’t imagine there being a problem running drilled on the street. Again it really depends on what you do.
I don’t know what Astro is talking about “unsafe” except all his post are advertisements so take it for what is worth. Like with the exotics, the drilled definitely look very cool. The other benefit to the 2 piece, aluminum center it that is saves something like 35 lbs of rolling weight, lose the stock wheels/rims and you are at 90 lbs give or take.