You might ask a Lexus mechanic about the process...there may be an easy trick to it.
I had brought an 86 Cavalier Z-24 in for some routine service once, and was able to talk to a mechanic when I picked up the car. Since the 6-cyl engine was mounted transversly, I asked him how to get to the plugs on the side of the engine facing the firewall.
He told me that they undo the rear motor mounts, and then they can tilt the engine forward, giving them easy access to components on that engine bank...how slick!
Perhaps there is some type of similar trick that allows easy access to the plugs on your car without having to pull the throttle body...I doubt Lexus engineers sat around a table devising impossible methods for replacing simple components.
By the way, I don't believe all of us here are anti-Lexus...everyone has a right to his/her preference to a particular vehicle without having to get bashed about it. There are many personalities, and so there are many cars manufactured to suit those personalities (although I am curious of the personality that takes their hard-earned cash and drives off with a wood-paneled station wagon).
I own MBs originally out of coincidence, then later out of love for them. I grew up with my Dad owning at least one. He still has his 71 280 SEL...and a 1999 Lexus LS400...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car