Hi Ronie,
I have been taking my is250 to my mechanic for the past 3 years and have been very happy with the work they do. They always use genuine parts unless customer requires for aftermarket parts and will always show any parts they have replaced. They work on a variety of lexus from what I have seen. They have been there for over 30 years and have very good customer service.
If interested they are at:
Steve's automotive services & repairs
164 Sunnyholt Rd, Blacktown 2148
(02) 9671-7529