Both the Brembo Redlines and AP Racing HSV Brakes will fit and clear.
A lot of people have mentioned that the HSV brakes will look better.
To be completely honest, if you are buying used calipers, the changes are that they will be scratched up, and not in prefect condition.
The HSV Calipers have the HSV logo painted very thinly on the caliper, and the Logo fades very easily, which actually looks pretty bad as the calipers age.
There is not much difference in stopping power between the Brembo (Redline) fronts, and the AP Racing 4 Piston (HSV) front brakes.
The AP Racing Brakes are better due to a larger rotor, and the rotor having a curved slot (Standard) when compared to the Brembo stock rotor.
But if you are fitting used calipers, then this is thrown out the window, as you would probably want to get a good quality rotor such as DBA4000s
Brembo front brakes (Redlines) used can be had for around $600 to $800, depending on the quality, age and kays of the rotor.
AP Racing (HSV) front brakes only are as rare as hens teeth, so you are looking at $1400 - $1800 for equivalent to the Brembo fronts.
I got my Brembo fronts for $700 which included rotors and pads that had only done just over 10,000Kms.
I got AP Racing (HSV) Calipers for the rear for $700, and I bought new rotors and pads from GSL for around $550.
If you are really interested in how they look, I STRONGLY suggest you get the calipers re-sprayed, fit new vinyl stickers, and add copious amounts of clear coat over the whole lot so as they look good for years to come.
(Trust me, if you are buying used calipers, they ARE going to be scratched up, have faded emblems, and will require a good clean to look "good".
I hope this all helps.