Big brake master cylinder

Hi has any used  Audi 80 Coupe  Master cylinder and servo the master cylinder diameter size of 25mm which is a jump up from 22mm offered in  Corrado and mk2 golf im wanting to fit  Porsche brembo breaks with 305mm disks  

there are a coupel audi 25mm oens out there as you say, it shoudl be ok if you convert to mk2 servo. theres a 25mm one from a transporter which fits mk2 golf you may find works out cheaper, part number is 7D0611019A

Thanks for info I should of said it's to go in a mk1 caddy I'm wanting to do full big brake  inversion  With g60 instead of drum on the back brembo up front