bluntys1rsturbo

hi everyone i am currently having an hybrid turbo built for me by wilky on the existing t2 frame so obviously will be using the oe manifold set up, now i know space is tight down there but im wondering the following

can i fit a larger compressor housing eg t25 size
can i fit a larger exhaust housing and if so whats the largest we can go to without problems?

any help much appreciated