Brakes of the different models are exchangable.
For an upgrade the big brakes of te Aero (302 and 314 mm) and TurboX are often used. For the rear brakes the ventilated 292mm can be used. In order to maintain a good braking balance it is sensible not only replacing the front brakes by bigger ones but also the the brakes at the rear by the 292mm discs.
Aero brakes 314 mm
Hirsch Performance offers an accessory upgrade for the 9.3-II but only for the front. These HP-brakes – made by ATE – are identical to those of the TurboX with a disc diameter of 345mm and a caliper that is slightly different to that of the 314mm brakes. The brakes of the Opel/Vauxhall Vectra/Signum /OPC/VXR are similar to the Hirsch and TurboX brakes. The only difference is that these are painted blue.
See also Hirsch Performance
Hirsch brakes 314 mm
Speedparts Sweden offers upgrades for the front as well for the rear. For the front there are two options: six-piston calipers for grooved and cross-drilled discs of 336 and 360 mm, respectively for 17" and 18" wheels. For the rear a six-piston caliper with a disc of 332 mm is availble. All discs are grooved and drilled and composed of two parts. www.speedparts.se
Brembo has a kit with four-piston calipers and ventilated grooved discs of 315 mm and stainless steel braided brake lines
AP-Racing has a four-piston and a six-piston caliper with grooved composite discs of 330 mm in their program. Available from http://www.abbottracing.net
WP-Pro presents high performance kits with six and eight-piston calipers and grooved and cross-drilled composite discs plus braided brake lines and hp-pads. Available from a.o. www.partsforsaabs.com
The above mentioned brands are sometimes offered by other companies under their own name.
Goodridge brake lines: the stainless steel braide brake lines have the advantage above the standard brake lines that hey don't swell when braking with more braking power as a result. These are often used to get better perfoming standard brakes and are the finishing touch in an upgrade.
Brake discs: there are many possibilties for brake discs. The standard 'smooth' discs are good enough for every day use. OEM were several brands used such as ATE, Brembo and Zimmermann. All these and a good number of other manufacturers or brands offer different types of discs: standard, high-carbon, sport discs: grooved and or cross-drilled and ceramic for better performance. Preferences are strongly dependent on taste (for the looks) and driving style.
Brake pads: this is more or less the same as in the brake discs. Ther is a lot of variation on the market but in general ther well known brands like ATE, Bosch, Brembo, TRW e.d. supply good pads for daily use. For the sporty variants like green, yellow and red stuff passes the same as in the discs: strongly depening on taste and driving style.
Brake fluid; Any good brake fluid meeting the DOT4 standard is fine for normal use. Sporty drivers may be better off with a High Performance DOT4. Refreshment on a regeular basis is advisable since brake fluid is very hygroscopic and looses quality after some time. Water in the brake system may cause corrosion to the calipers and pistins in the long term.