Porsche dealership want $2,300 wants to replace brake booster and master cylinder

[bwdz]

You need to diagnose what is wrong first not just replace everything and certainly this is an easy do it yourself with basic tools and not a $2300 job. A very hard brake pedal, works at first and then gets hard, is often a problem with the booster and not the master cylinder. It is possible that it is just the check valve since you have brakes at first. Never messed with the booster on the Boxster so I don't know where it is but I am sure someone here does.