Maybe check if the batteries are installed the correct way. Or take it to Lexus and get them to check it.
I have had no problems with mine except the batteries going flat.
Enjoy your ISF they are a great vehicle. from your photo the rear mag wheels are on the wrong side of your ISF, the blades are facing the wrong way, they should be the same as the front mags. you should swap them over.
Another GS300 LTuned excellent. Back in 2013 I had my GS LTuned mag wheels resprayed by Lexus of Chatswood service centre. you are correct that they are a different colour to the normal Lexus silver that they use on their mag wheels. I’m not sure of the correct paint code. You could take your centre hub cap & get it scanned at a paint place? or you could get Lexus of Chatswood service centre (Phone: (02) 9406 8388) to paint them for you.