I don't think your RX300 wants grey wheels - but you're on the right track!
There is a man with a van who will come to your house and respray you wheels - they will look like new.
He can also fix any chips you may have from kerbing.
He takes each wheel off, masks the tyre and sprays the wheel. Doesn't take long.
My neighbour had his X5 wheels done - looks a treat now!
Nice looking car you have though. Mine is the same year, 130k and still like new!
Jon