for a friend of mine sometimes is cruise control would work and other time it wouldnt so what he did was get the wiring checked and found out that one of the wiring had burnt out so that was what was the problem with his CC what was yours?
Check the inflation of all tires, and see if any tire has hump. Hump is manufacturing defect and you havent done anything wrong or the bad road havent done anything. It must be there before but now you notice more as pay more attn.
Lexus is not very complicated car, so dont bother so much on expert assistance. Anybody who work on toyota can very easily work on Lexus. Stroll around al quoz or Ghusais and you will find plenty of good workshops.