Hey Zinc,
A RX330 is a great car thats been designed and made with quality.
Cant comment on service costs as I do all my own work but can answer your questions as best I can.
1. The scehuled maintenance by the book is every 10K km, that would be essentially an oil & filter change.
2. The 80K service is just a (tappet) valve clearance noise & engine vibration check at idle & adjustment if necessary on top of the regular service
The 100K service is a spark plug change on top of the regular service
The 150K is the major service which timing belt gets replaced, but thats pushing it and majority of timing belts should replaced at 100K km mark to be on the safe side. Prevention is better than cure!
3. ONLY get it if its the extended Lexus factory warranty, if its any other type of company extended warranty its not worth the paper its printed on. $2K is a small price to pay for peace of mind if something MAJOR goes wrong!
4. Check that service history schedule has been followed & if its done more than 150K km check the major service (timing belt) has been done.
5. You can also have it serviced by Toyota dealerships, same diff!
6. Find a mechanic who you can trust & is confident in servicing your car & stick to them, as they will become familiar with your car history over time.
7. Always read the fine print!
Hope that helps :D