Yes
Close. mid range grunt is superior in the 3.0 liter.
A few well-documented annoyances. (Display pixels, door seal creaks, seat back clicks). The only six reliability issue would be the early 530's aux fan relay ... make sure it's been replaced. Sometimes individual ignition coils fail ... easy to replace, but a bit expensive for a stinking coil.
Later cars are more apt to have the high-OBC (more computer functions and "check display" versus graphics ... you pay more and you get "door ajar" instead of a graphic description of which door it actually is!) ... not sure its worth it, just more pixels to fail.
Don't pay a premium for the DSP radio. It wasn't a significant improve over standard for $1200 increase in sticker price.
Xenon low beams are very desirable.
I'd recommend the sport package unless you live in pothole central.
There are four seat options: standard, standard with lumbar, sport seats (lumbar not available, but perhaps DIY installable), and comfort seats. Sport seats are a love 'em or hate 'em proposition ... they either fit your body or they don't. Comfort seats (fairly rare) never get complaints.
I'd try and find a car in which the owner went above and beyond standard maintenance. A 525/530 can go over 17,000 miles before the oil service light comes on. That's too long IMO. I'd also steer clear of a high mileage car that never had the trans fluid changed (particularly an automatic). "Lifetime fill" my ass! I've read several tech articles that note that BMW service requirements suddenly doubled after "free" maintenance programs were initiated. I think an owner that adheres to the stricter, pre-free-maintenance schedule for maintenance and fluid changes might be selling a superior car. Certainly one that has the deck stacked in the favor of a long service life.
R / John