The Brake Rotor Controversy

Plain, slotted or cross drilled?
In 1998 BMW M models came with plain rotors.
In 2010 the M3 comes with drilled rotors.

Do slots or holes or both actually help?
After much searching I didn't find anything I'd call authoritative on the subject. I chose to go stock solid rotors. The information from brembo at tirerack.com helped make my decision. (the brembo logo uses a lower case "b"). I ordered stock rotors and ceramic pads - rotor and pad replacement video to follow.

The bottom line is that in their advertising brembo appears to emphasize the appearance aspect of the slots or holes rather than the performance aspect. They indicate that drilled rotors should not be used with racing brake pads at all.

Here is the actual verbiage -

brembo Sport Slotted Rotors
On the "Product Description" tab is the following disclaimer:

"Brembo Sport slotted brake rotors are designed to meet the challenges of high performance street driving while adding an authentic, race-ready look.

NOTE: Brembo Sport slotted brake rotors can be used in conjunction with race compound brake pads on the track for drivers’ schools and lapping days.

IMPORTANT REMINDER: Slotted, drilled or dimpled rotors offered as OEM replacements should not be considered appropriate for high-speed track use.

While grooved, drilled and slotted rotors offer an enhanced appearance and add some resistance to the boundary layer of gasses that can build up between the pad and rotor, they are not designed to withstand the extreme temperatures that are produced on the racetrack. If they are used on the track, it is very important that the rotors be carefully inspected and should not be driven on if even minor signs of deterioration are seen. Note, too, that if any products are used on the track they are not warrantable"

brembo Sport Drilled Rotors 
On the "Product Description" tab is a similar but slightly different disclaimer:

"NOTE: Brembo Sport drilled brake rotors are not recommended by The Tire Rack for track use or intended to be used in conjunction with race compound brake pads on the street. For severe duty brake demands see Brembo Sport slotted brake rotors.

 IMPORTANT REMINDER: Slotted, drilled or dimpled rotors offered as OEM replacements should not be considered appropriate for high-speed track use.

While grooved, drilled and slotted rotors offer an enhanced appearance and add some resistance to the boundary layer of gasses that can build up between the pad and rotor, they are not designed to withstand the extreme temperatures that are produced on the racetrack. If they are used on the track, it is very important that the rotors be carefully inspected and should not be driven on if even minor signs of deterioration are seen. Note, too, that if any products are used on the track they are not warrantable."

brembo Replacement Rotors have no disclaimer. Maybe it's because they don't think people will track plain rotors and so they don't need a warning.

brembo has it's own website. The advertising there indicates benifits in water, to dissipate heat and eliminate brake dust and gases.

Convertible Rear Window Cover

BMW didn't start putting glass windows on the rear of a convertible until the E46 in 2000.
So, if you have a BMW convertible 1999 or older you have a plastic rear window.

The plastic scratches during normal use. Convertible tops wear during normal use.
Having a cover over the window when putting the top down helps reduce wear.

You can buy a cover or make one yourself like I did.