necessary internals for ko4 upgrade and uni chip, 02 jetta1.8t

I need advice on what internals I will need to upgrade, as I am buying a BW ko4 turbo upgrade kit, and putting the unitronics software upgrade on as well.  The unitronics guy tells me what they do for the stock engine w the ko3 is program the boost to 20psi.  Since I'm getting the larger ko4 I know I can put the boost even higher, say no more than 25psi.  So I was wondering if I would run into any problems running 25psi with a ko4, uni software with the bone stock internals.  I know I'll need an intercooler before the chip, thats a given and I already have an intake, turbo inlet pipe, and forge007 diverter valve, and  stiff engine mounts FYI.  But will better, forged pistons, new fuel system, camshafts, headgaskets, etc be necessary for safe and reliable power?