My rear 235s were showing signs of overinflation when I changed them recently (down to TWI in the middle, 4mm at the oustide edges!). During most of their wear I didn't own the car but there is not huge weight over the rears with an empty boot (and a lot of weight with a full boot and back seat) so it would probably be more prudent to adjust the rear tyre pressures according to load (although it's easy to forget). I was running mine at 34 but am going to reduce the rears to 31 and see how that goes.
Fronts should see less load variation due to them supporting a cast iron V6 all the time!
I don't think the mythical "italian tune-up" is necessary not does it make much difference how an engine is driven once it's run in, but if you've got it, you might as well use it every so often!
As long as it is serviced regularly (more so than the manufacturer's recommendations!), ideally doesn't spend all its' life on shopping trips but gets a few long motorway journeys, and, most important of all, isn't ragged from cold it should be fine.
Kevin