This has become a hot topic lately, a few people have ordered or are about to order an upgraded rear arb and many more are asking about it so I reckon it would be helpful to have this information gathered in one thread, instead of scattered in various (sometimes not even related) threads. Information about possible options, installation and reviews of-course.
I've went for the H&R 25mm one, the model number for the 2.0T 272/280 AWD cars is: 33581 HA5.
The model number for the 2.0T 220 FWD is: 33851 HA for the 24mm one and: 33851 HA2 for the 26mm one (apparently the FWD has two options)
The bar already arrived today but I will hold off installation until I get the replacement OEM bolts and nuts on Monday, needed for the job. Below is the illustration of the items from the Skoda manual as well as a small table I made with all the involved fasteners for upgrading the rear arb and end-links (if needed), numbers and torque figures.
FASTENERS INVOLVED:
# in Skoda manual
Title
OEM No.
Torque
Quantity
REPLACE
Tool
#4
Bushing bolts M8x30
N10765801
20Nm+90
4x
YES
Triple square No.10
#6
ARB to droplink self_locking nut
N10286110
55Nm
2x
NO
16mm socket + Triple square No.6 for inner screw
#5
Hex head bolt M8x85
N10776501
-
2x
YES
13mm socket
#2
Hex nut
N90183804
20Nm+180
2x
YES
13mm socket
UPDATE: Link of a very clear video of the installation on a Mk7.5 Golf R (identical setup)