The European Nissan N16 Service Manual states the following brake specifications:
Master Cylinder Diameter: 15/16" (23.8125mm) - For QG15DE, QG18DE and YD22DD engines
I was pretty happy as 15/16" size is common to the SP and set about designing a Wilwood BBK (Big Brake Kit) along similar piston sizes as what was initially done for the SP (~1.38" diameter per piston for a 4 piston caliper). Then one day while cleaning the master cylinder on the Slowtra I saw the following embossed on the Slowtra's master cylinder - 7/8". This immediately registered horror and then disgust as 7/8" is only 22.225mm which is smaller than 15/16". If the total caliper piston area of your upgraded BBK is too large for your master cylinder the term "pedal to the floor" will definitely ring a very painful, expensive and dangerous bell!
A quick check with the TCEAS parts center confirmed my nightmare. The MYDM N16 1.6 SG Manual comes with a smaller master cylinder compared to the SG-Lousy and 1.8 XG-L variants. Bummer! This means I would need to "upgrade" my stock master cylinder. And how much would a new master cylinder cost me? "RM1070 after discount" said the enthusiastic TCEAS technician. RM1070 just for a master cylinder!!! Once I pick myself up from the floor I quickly said "Thanks but No Thanks" and have decided to look for an excellent condition pre-loved 15/16" or even 1" master cylinder from my regular contacts. Picture below of the Nabco master cylinder on the Slowtra. Talk about spec and cost cutting :( The N16 Service Manual also lists a Tokico master cylinder which is different so be careful what you get.