Cema wrote:Are you telling me that 2 replacing my 2 parts T12 HC Ret by 2 parts T13 HC Ret would make me loose dps? My personal thoughts on this were that the dps gain granted by the bonus were roughly the same but that the strengh increase on T13 HC would make the difference. So were is truth?

Yes, stick with T12 HC Ret.
Why: The DPS gain granted by 2T12 Ret
is smaller than 2T13 Ret,
for Retribution. Remember that they cast CS less than us (33% less, roughly), have a longer 0->3 HP ramp-up time (13.5s for 3 CS's rather than 9s for us, which is often lower thanks to Grand Crusader), and TV represents a much larger damage increase than SotR. Ret DPS is very heavily dependent on HPG, so getting HP from Judgement is a very large DPS for them.
Because we cast more Crusader Strikes, and because CS makes up more of our damage (30% or more, usually), the DPS gain from 2T12 is uncommonly large. Similarly, at high hit/exp, our rotation ends up having very few empty GCDs. Remember that SotR hits (not crits) for roughly the same as J or AS. So we don't gain as much by casting more SotR's, especially because it generally means we have fewer Sacred Duty procs to make them auto-crits.
As a result,
the simulations I've run show that while T13 Ret 2-piece is roughly 1000 DPS at low hit, it drops to around 400 DPS at hit/exp cap (and less yet if the boss can't parry, like Ultrax).
You can estimate the gain from strength easily enough. You're probably using T12H ret gloves/legs in your Ultraxion setup, but let's do a best-case scenario where you're considering upgrading the helm/chest instead. You gain 89 STR from the helm slot, and around 129 from the chest (it's actually a little less effective than this, since you can use a hit/str gem in the T12 chest for extra DPS). That's 218 Strength, at
around 1.4 DPS per point (strength is a weak stat for us), or around 300 DPS.
So you sacrifice a 1k+ DPS proc from 2T12H Ret to gain a 400 DPS proc from 2T13H Ret (and possibly less - again, Ultrax doesn't parry, so it's likely less than 300 DPS) plus around 300 DPS worth of STR, at most. Still a net loss.