i don't know why but i always seem to disagree with you army,sorry
To check for sludge their is going to be a tear down
you will never get a new engine as even crate engines are not new they are just rebuilds wether they come from japan or the USA.
Only new cars get new engines or unless it is reassembled peice by peice by a engine builder and all the parts ordered from toyota where you will get new parts .
Check the engine mounts they may not need changing that is all that is needed to look at that would save tiem or money now barely
The easiest thing is to always use synthetic oil and not skip oil changes.
second *army* ,stop making assumptions with no information to make you thought credable
How would you know who contracts out rebulds or not.
First the information has never been given to us by the owner who is looking after it,
it could be lexus paying the dealer to do a tear down and replace what is needed ,wether it is doen by them in house or down the street at uncle toms.
lexus providing the engine and paying the dealer to do the labour
come on now stop guessing