Replacing the H80is fans with something quieter (aka slower) generally brings its performance down to that of the $25 Hyper 212. So be aware that is ya cut rpm, thermal performance drops precipitously. With that in mind:
No need to go ugly.....well, depending upon how much performance you willing to drop. On cases, coolers and quiet rad applications, Noctua is no longer the king of the hill..... hasn't been for over a year now. Phanteks is both quieter and produces more cooling by quite a significant margin
But again, the PWM version of these fans is not LED.
The question is .... though the Phanteks has 120mm mounting holes, it's a 140mm fan. You won't be able to take advantage of the lower noise and better cooling if it don't fit in your case. And remember while brand name and design is good for small advantages .... no brand's 1500 rpm fan is going to come anywhere close to the cooling capacity of the 2700 rpm you have on the cooler now.
Here's a Corsair unit at 1700 rpm losing out to the $25 Hyper 212.
So adding $25 fan to the $95 H80i to get lower noise doesn't make lotta sense if you will be dipping below the thermal performance of a $25 cooler.
Don't fall into the mindset because Noctua makes great, quiet 1500 rpm fans that this somehow correlates to their faster rpm lines. Noctua had different design goals for the faster fans and their 2000 and 300 fans are by no means quiet.
the H80i is listed at 37dba ....
The Noctua 3000 rpm job is rated at 45 dbA *
The Noctua 2000 rpm job is rated at 30 dbA *
* and that's without the noise caused by air turbulence thru the rad
So you have quite a dilemma facing you ..... it takes a 2 x 140mm rad on an AIO (i.e. H110) to match the performance of an air cooler like the Phanteks PH-TC14-PE or the Noctua DH-14. The single 120 x 120 mm rad based AIOs make up for that on 1 x 120 rads by using extreme rpms and oft peeps want to quiet them down.
The Corsair 2450 rpm fans will do the job almost as well as the stock noise and be slightly quieter but still noisy. The 1500 rpm ones will produce higher CPU temps than the Hyper 212.
The popular Noctua 1500 rpm quiet models are in the same boat. as the Corsair 1500 models but just a lil bit better than the Corsairs.... The Phanteks models w/ 120mm mounting holes are a more significant step up, if they fit in ya case (they will mount to rad) but still well short of the 2700 rpm fans cooling performance. If you thinking the 1500 rpm Corsairs or Noctuas might be the solution cause you don't need the thermal performance at your planned OCs, the Phanteks will do better thermally and noise wise. However, no 1500 rpm fan designed for radiator usage can can compete with a 2250 - 2700 rpm fan designed for radiator usage.
The Noctuas, Delta's and other fans in the 2000+ rpm category will suffer from the same problem..... as thermal performance increases so does noise.
I'm not familiar w/ Corsair link but I dunno how it would distinguish one PWM fan from any other. Remember again, the Phanteks are somewhat bigger than standard 120mm fans tho not as big as standard 140mm fans. Their 120mm mounting holes will mount on the rad no problem but they are bigger than the 120s and if case limits space to as 120mm, might not fit