Bostech

I am so disappointed as I bought Lexus ES 350 and have 02 and 06 RL (was thinking about selling 02 but good chance I might keep it if I can fix it and sell Lexus) so now I run into 2008 RL at local dealer for $1800 for 195K with bunch of problems and I have no place to put it until I sell Lexus and hopefully fix and keep 06 and 08.
Car is shaking/hard to start with bunch of codes.First thing I noticed is rust and seems it was driven only on Florida so likely near beach.There is coolant liquid around tank but not under hood or other side,below entire area looks rusted more than normal and negative cable connector is also heavily rusted.I could not see anything else from top.
Car has codes P0134,P0430,P0305,P0301,P0300,P0302,P0304,P0303,P0 306,P0137,P2237,P0325,P2270.
So looks like misfiring on all 6 cylinders,O2 sensors bad,knock senor bad,catalyst system bad...I wonder if this is worth messing around. Sounds like bad sensors and maybe leaking valve covers giving these errors or is it major engine issue.Rest of car looks in OK shape.Engine sounds strong despite all of errors and shaking and trouble starting.I was not able to drive car at all,just start it and look around.