Head Block Question

So I've got a S-13 SR20det it's at a machine shop now they are going to do some mild head work and put in ARP head studs and a better head gasket My plan is to run a T28 turbo but I know that I will have to modify the oil and water lines to make this work so I was wondering has anyone tried running a S-14 or 15 head on a S-13 block and would this solve any problems the little research I have done made it sound like the power improvements of the 14 or 15 were in the head and turbo. Let me know what you think. Thanks

if your heads at the machine shop why would you choose a different head??

Kustamogenif your heads at the machine shop why would you choose a different head??  

They haven't started the work and if a different head would be superior then I would rather just start with that if it isn't cost prohibitive.