My RX300 had similar noise since about 6 mo. and the 30K mile service was recently done. The dealer could not 'reproduce' the noise, and it didn't make the noise while cold, so nothing was done. However a different dealer , now in warmer conditions accompanied me for a drive and was able to confirm the noise. Guess what?? They have chosen to replace the whole engine. As it is less than 4 yr. it is covered under warranty. I hope this fixes the problem. Well as you can tell, the dealer who says it is 'normal' dosen't know what he is talking about. Try a different dealer.
