To be bluntly honest here, I feel like trifecta makes a lot of claims and uses a lot of super technical jargon to describe pretty standard ECU functions in an over complicated way and not all of them seem to work as they claim...
ARPM is cool, but does it truly work the way they claim? I dont think so. If it did, when yall added fuel mods, meth, fuel cams etc, you would be making a bunch more boost than before with no need to retune, right? The factory fuel system lacks a lot in lower ranges, would think if the ARPM truly worked how they claimed, it would add a bunch of boost in all these ranges where the fuel supply had been increased.
Same thing with the whole bi direction enhanced knock control and zoning, just an overly complicated description of the 6 existing factory knock sensors that does the same thing stock and tuned with HPtuners. Then they claim the tune will 'adjust' for high octane fuel on its own, something that has been discussed a bunch and IMO, proven to be bullshit a few times. Theres a reason trifecta now offers seperate high octane tune files, because the claim that their tune would automatically adjust was BS. All tunes adjust knock based on 100 different factors. These ECUs are insanely complex, its never a black and white scenario with these cars.
As far as fuel pressure goes, well early on a lot of tuners came from the LS world and such, didnt really know what to expect, were running these cars like a port injected car 11.0-11.5 AFR ratios and pushing too much boost, putting lots of stress on the fuel systems and had manage to run a few cars super lean at high speeds causing damage, burnt valve on the only car id ever seen hurt
Scott @ tapout has never done this to anyones car and if tuned properly, is not an issue. With the cars air/fuel in line where it should be as a DI car and being reasonable with boost demands, there is no concern of dropping rail pressure.
And the stock security measures are still in place so if the rail pressure drops to low, it will send the car into limp mode as well.
With all that said, i still think either would be a good option, trifecta is gonna be a plug and play solution if he just wants to tune it and go and not mess with hptuners or anything and truly plans to stay tune only forever, id agree that trifecta may be the better option for his needs.