I think it's a good idea to start a list like this to help users to make their choices easily.
Stock
Front : 18mm
Rear : 14mm
ST suspensions
Front : 19mm,
2 way adjustable. 41% & 76% stifness increase
Rear : 17.5mm
3 way adjustable. 20%, 58% and 133% increase in stiffness
Witheline
Front : 20mm, 22mm
20mm Fixed or 2 position in option, 22mm
2 position
Rear : 16mm, 18mm
3 position
http://www.whiteline.com.au/do_segue...ehicle=2012-ON
Cusco
Front : 16mm, 20mm
1 position
Rear : 14mm, 16mm
1 position
TRD Stabilizer Set
TRD Site
Jparts Site
Eibach
Front : 25mm
2 position
P1 = 88 N/mm (500 lbs/in) +255%
P2 = 103 N/mm (585 lbs/in) +314%
Rear : 19mm
2 position
P1 = 45 N/mm (255 lbs/in) +126%
P2 = 60 N/mm (338 lbs/in) +200%
http://performance-suspension.eibach...-roll-kit_2013
Hotchkis
Front : 25.4mm
2 position
500 lbs/in (170 % Stiffer than Stock)
630 lbs/in (245 % Stiffer than Stock)
Rear : 19mm
4 position
320 lbs/in (200 % Stiffer than Stock)
405 lbs/in (275 % Stiffer than Stock)
520 lbs/in (385 % Stiffer than Stock)
700 lbs/in (550 % Stiffer than Stock)
http://www.hotchkis.net/scion-frs-sp...sway-bars.html
Perrin
Front : 19mm, 22mm
2 position
19mm Hole #125% Stiffer than 18mm OEM Bar
19mm Hole #272% Stiffer than 18mm OEM Bar
22mm Hole #1130% Stiffer than 18mm OEM Bar
22mm Hole #2218% Stiffer than 18mm OEM Bar
http://perrinperformance.com/i-13324...-fr-s-brz.html
Rear : 16mm, 19mm, 22mm, 25mm
3 position
16mm Hole #130% Stiffer than 14mm OEM bar
16mm Hole #265% Stiffer than 14mm OEM bar
16mm Hole #3116% Stiffer than 14mm OEM bar
19mm Hole #1150% Stiffer than 14mm OEM bar
19mm Hole #2243% Stiffer than 14mm OEM bar
19mm Hole #3347% Stiffer than 14mm OEM bar
22mm Hole #1400% Stiffer than 14mm OEM bar
22mm Hole #2535% Stiffer than 14mm OEM bar
22mm Hole #3729% Stiffer than 14mm OEM bar
http://perrinperformance.com/i-13324...-fr-s-brz.html
Tanabe
Front : 22mm
1 position
http://www.tanabe-usa.com/rnd/?tag=/fr-s
Strano FSB
Front : 22mm
1 position
85% Stiffer than 18mm OEM bar
http://www.stranoparts.com/partdetails.php?PartID=928
SuperPro
Front : 20mm, 22mm
Rear : 18mm, 20mm
http://www.fastwrx.com/suswbafbr.html