1. Gen3 RX350's handle much better than the Gen1 and Gen2. I have the a Gen 2 04 rx330 and a gen 3 10 rx350. My RX350 handles like a car and is VERY fun to drive on the highway taking corners. I really the gen 3's, more nimble and again tuned for more driver enjoyment.
2. If you get the ultra premium package then the leather is very soft and supple. If not, then the leather is a bit harder. Overall, build quality of the interior is great, but nothing like the gen1 rx300. As time goes by, costs go up and blah blah, so the cars nowadays don't have the same quality interior as the 80's and 90's Toyota out there. But the interior on the new IS and GS is a huge turnaround than previous. I do like the interior of the Gen3 more than the gen2, but still a bit plastic imho.
3. Still cannot adjust regardless what seat you're in when the vehicle moving. Lame!!!
4. Still timed.
Hope this helps.