I wouldn't recommend the Lexus pads because they can squeal and create a lot of dust. If you wanted to stick with Lexus genuine parts then you could go with the alternative pads that were made available for the RC F that some people had replaced under a TSB to stop squealing but for some reason Lexus GB didn't extend the TSB to the GS F (you just shouldn't put the car on a track with the alternative pads).
Personally I switched to EBC Red when I had my GS F, mainly to get rid of the low speed squeal but the lower dust was welcome as was the cost saving.
Nothing wrong with the Lexus discs, other than price. The Brembo aftermarket ones seem to be of the same quality as OEM, other than the anti-rust coating which has possibly been improved since Bluethunder purchased some (or there are different parts; some with and some without coatings).