Hi
im new too, also got a gs300 1999.
mines got 87k miles on the clock, got the car saturday. the last time it was changed was at lexus at 67k, im not doing mine till 100k.
from searching previous posts on the forum, some people pay £300 up for a local garage to do it.
i dont think lexus will charge too much, its always worth pitting the dealers against eachother to beat prices. ring a few dealers up and get quotes.
might bag yourself a stamp in the book!