I'm in the habit of getting Lexus to diagnose my problems then I can choose where and who to use for repairs.
For example my lower control arm bushes are shot, Lexus won't replace the bushes but only the entire control arms. £300 a control arm just for the part, I need both sides so £600 in parts plus labour and VAT and the bull would be over £1000!
I bought the bushes for £20 each from ebay and am paying a garage £70 in labour to change them. So what Lexus wanted £1000 for I'm paying £110 :)