do you have clutch problems, or noises?
If not, I wouldn't care. Clutch and dmf life may be 30.000miles as well as 200.000 miles.
the original part you should be able to get it for about 1.000 eur as aftermarket replacement part. Contact aftermarket parts specialist.
I don't think, but I even wouldn't try, as it will create lots of problems, vibrations and stalling.
If you want to save, you can get "original" non-dmf replacement, however even this is not recommended because higher vibrations may have impact on other engine parts (at least on silentblocks).
You know, DMF plays important role in keeping the engine smooth. You bought lexus for silence and luxury so don't kill it...