Sorry just seen this question, If the Roush ECU you have was going to be fitted to a MG ZT385 it should work fine. However, realistically I`d be very surprised if you have an original MG ZT 385 ECU. You may have one that was going to be fitted to the MG SV-S? Either way Jamie from Jam Sport Racing used my standard ECU and remapped it. (approx £400 to £600 as he did with Re-Treads `Dave` ECU) My Vacuum set up differs from Dave?s and other Roush engines I have seen? Possible because I fitted the S/C to my engine whereas Dave?s fitted a new engine with the S/C already attached.
Hope this helps
PS, Can I ask where you obtained the S/C and bits from?
Regards