I have never had durability issues any were even close to the milled section, if fact the LW version is milled even more with no issues there.
The only issues I've had are at my home track, myself an a couple other running these chassis have bent the kick up area, that being said I've bent the stocker as bad if not worse before, but no one else has had any issues with durability. I've been looking into ageing to try fixing that issue that mysef and locals are having