Did some searching and got some good and bad info..
Or just more confused

Car 98 Honda Civic HB CX stock

Parts that I have
-ek9 prop valve
-94 integra rear disc brakes
-99-2000 Civic knuckles brakes etc Si USA SiR Canada

I want to upgrade the master cylinder stock is 13/16

I was told the 98 integra RS has a 15/16 and will bolt right up..
Not sure if booster is the same.

But the CTR EK9 comes with a 1 inch master..

Which is the same as a 98-2001 ITR or GSR has the same master cylinder numbers and booster numbers..

Going by this post the GSR, ITR booster is alot larger then the stock booster..
https://honda-tech.com/zerothread?id=818263

https://honda-tech.com/zerothread/1998336
https://honda-tech.com/zerothread?id=818263

thanks guys