Yes your mechanic should recognize them. Metalmasters are a type of metallic compound brake pads and powerslot is a brand of aftermarket rotors.
Metalmasters are by PBR Axxis. They are said to produce less dust than stock. I use PBR Axxis Ultimates which are ceramic compounds. These are not considered low dust but are said to be less desistant to brake fading and supposedly
last longer. This depends on how hard you push your car. As previously mentioned city driving takes a greater toll on the life of brake pads.
Seeing as you are a novice I doubt you would need anythign more than metalmasters. Pads are cheaper when you order them online. I always order my pads from www.turnermotorsport.com
. Ive doen research and their pricign is great and shipping is fine too. Don't worry about changing your rotors, just buy the pads and bring them to your mechanic. Pads are easy to change if you got tools, if not your mechanic shouldnt charge you more than $35 to put in new pads.
Oh, and welcome to Bimmerwerkz.com!