custom ct26 highflow Q?

[mk3_7m]

hey guys im getting my ct26 turbo highflow and using non toyota internal and with a steel wheel turbine. the guy has actualy advise that he can highflow and install 76mm compressor with 56mm Turbine? would this be a laggy set up? what can you guys advise me for more of a responsive set up as ell as give top end. so that i can advise him before he mod my ct26.

there website is here
http://www.digi-hardware.com/atr28.html

thanks guys