I have z32 brakes on my S13 and they're the smallest brakes I'd run on a KA car. The Q45 brakes run larger rotors (11.8", I think) with dual piston calipers. Mechanically, they are more powerful than 300zx brakes because of the larger rotor diameter. The only thing I'm not sure about is the aftermarket pad availability and heat capacity. If I came across a cheap set, I'd do them. I'd say the Q45 brakes are good on any N/A KA or stock turbo SR that only sees the street or drift events.