On LN's website it says two year warranty for the LN retrofit, but that doesn't cover the labor nor anything that will need replacing in case of a failure.
They RECOMMEND replacing every 6 years:
IMS - Products LN Engineering
But the warranty says 2 years:
Dual Row IMS Retrofit Kit for MY97-01 - IMS - Products LN Engineering
The engine won't blow up just because the garage didn't give you LN warranty nor do you have to change the bearing every two year
Meir and I both installed ours ourself, no warranty... at all, still running