@michaelrocchi the back plugs are a PITA. takes about 3-4 hrs. Since iFixit doesn't yet have a guide for this, use something like [https://www.youtube.com/watch?v=rBlti5IN3Mc|this video] or the great instructions [https://www.clublexus.com/forums/rx-2nd-gen-2004-2009/792543-rx350-spark-plug-replacement-guide.html|on here], to assist you with it.
While you work on your Lexus, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.
Repair is War on Entropy!