New roller rockers are $400+ shipping so $500 by the time they're at your door. You'd also need valve cover gaskets, coolant etc and you might as well opt for better springs and retainers and opt for a higher lift rocker.
Thats another $200 if sourced locally.
$600 for rockers.
I priced out a VS cam with L76 springs, LS1 retainers, new stock timing chain and dampener with fluids and it'd be around 900 IIRC.
200 dollars more for a lot more go. You'll also be replacing your valve springs and wear items in your timing set which all probably wont like seeing more boost and lift after 13 years and plenty of miles.
No point in cutting corners here.