From my experience very few aftermarket replacement parts are of the same quality or last as long as the OEM original replacement parts. The exceptions would be Denso, Aisin, Bando, and a few other. Even then the quality is sometime not the same as OEM even if made by them. They sometime have...
That weight is there to cancel out a certain vibration/frequency droning noise. Some people have removed it and have noticed a droning noise at certain speeds others haven't.
It's getting to the point where you can't go anywhere to get anything done, $475 is beyond excessive. That is why this website and everyone that contributes is so valuable. I have saved thousands on DIY repairs.
On my last two timing belt replacements, I have given the mechanic the heater tees...
The seat dimensions on the LX470 and Land Cruiser are the same. Only difference that I am aware of is the leather quality. The LX470 used a better quality leather.