Need to list the K04 tune you plan on going to. Most canned tunes require only the oem fprv 130 bar fprv. Even APR doesn't require you upgrade the fprv. The RS4 is a 135 bar fprv.
However, some custom tunes allow one to use a HPFP upgrade that can produce more rail pressure and thus would require a higher pressure limiting valve on the rail. Such as a company that makes stages of hpfp upgrades;
https://www.vismotorsport.com/20tfsihpfpupgrade
I had a tune once that had a 142.5 bar rail target. That is when I installed a 145 bar fprv. APR's stage 3, or S5 4.2L FSI V8, fprv is a 155 bar and would work for tunes when more than 130 bar target is set as the rail pressure target.
APR says their hpfp upgrade produces a bit more than a 40% increase in rail pressure.
Autotech says 50%.
VIS says their stage 1 = 55% more piston area.
So, any of these will suit canned tunes for a K04 w/hpfp upgrade, and no fprv is needed for canned tunes. I am back to my original GIAC K04 H.O. tune (requires an upgraded fprv)...and target never exceeds 140 bar per the H.O. tune.