Si (D16a6) Head is a non-vtec head so yeah you will need to get a vtec head first. you have a couple of options for vtec head.
D16y8
D16z6
Jdm D15B
But if i were in your position i would just get complete Y8 motor. Can be had for cheap and probably cost about the same and put out more power than D15/Y8 mini me.Just my
. But if you had A6 block wanting to put vtec head on ,i would do differently.
Also you still Have to convert to MPFI.