Barlowc: get the StopTech/Centric from RockAuto!! Make sure the pads are "Stoptech ST Street Performance Pads" and get SLOTTED Centric rotors, NEVER DRILLED. Slotted allow for the prevention of gas buildup between rotor and pad surface as well as stopping water from creating a barrier, they really help keep the pads' contact surface perfectly smooth and even, they don't compromise disc strength at all, and Centric makes them so the slots don't extend to the edge of the rotor face which is ideal.
Stay away from Brembo Blanks. They are worse than OEM, although OEM are decent... Point is, the Brembo blanks just suck. The company makes fantastic BBKs, and have one of the top caliper designs on the market for multi-piston calipers, but they are not especially known for the discs.
I personally went with Stoptech Monobloc calipers for my 4wheel BBK instead of Brembo's Monobloc offering because the ST kit was $1895 less, was 6piston/4piston f/r versus 4/4, has better pedal modulation and stopping power (in part due to more progressively sized pistons), reduced unsprung weight by a hair under 4lbs more than the Brembo kit, and the ST monobloc calipers, being one of their flagship products, are available in an awesome "bare aluminum" (I would call it a mix between brushed aluminum and satin nickel) with the StopTech logo in any color you want (I went with Red to match my BBS center caps) and they are coated in like 20 layers of some special ultra high temp clearcoat... Mileage in the 5 digits on the kit, street and track, and I swear just 3min with a hose and quick detailing spray and the brake dust is completely gone (been having my buddy who owns a body shop look into this stuff bc I really want to have some other parts coated in it).
Anyway, I have been using...you guessed it... Stoptech ST pads in them for street duty and I can't tell you enough how awesome they are.
I also have the same pads on my 325i, with the slotted rotors, and perfection! 1/10th the brake dust but 15-20% better bite. Win-Win.
Honestly, while you are replacing this all anyway, I say spend an extra $90 and get the 4wheel set of Stoptech Stainless Steel Braided brake lines... Pedal feel is significantly better, and they will outlast your car. You will never have to worry about brake lines bursting on a hot day, or even the brake pedal going to the floor, as these do not expand.
Throw in some Motul RBF600 brake fluid and you are set, my friend! That will give you excellent performance for 4yrs or more, easily double that if it is like 90% highway (although you will need to change the fluid, obviously).
Please, Private Message me if you want to know anything more, to see pictures of how they look on my 325i (non-BBK car, 328Ci has BBK but is stored for winter), sources for buying them, or anything else! I am HAPPY to help!
SteveSRT8: We agree! They really surpass everything else, don't they? My friend spent $8k on a full Brembo BBK for his '02 M3, the Gran Turismo kit with 8piston 15" front and 4piston 14.3" rear and after we installed my kit and bedded it, he was jealous! Granted, Brembos do have that look that is subtle but for those who know what they see, it says "I am a monster... My rotors are bigger than many cars' wheels!", although some of the subtlety is lost when they are bright red 8piston calipers with their 2pc 15" floating rotors both slotted and drilled (though their ultra high end drilled rotors, the BBK ones that are $500 and up PER CORNER, use some special manufacturing process, and the insides of each hole is plated with some exotic sounding metal like cadmium, never rust, and the holes vary in size from like 3-4mm to 8-9mm which helps load distribution or something... Those, I would be okay with having on my car haha).