Old post but given your timeframe figured I'd give my experiences.

I've driven a 328d. Not the touring but the sedan. Good solid car capable of mid 40's for mpg. My dad went from Pensacola FL to his doorstep in San Antonio and still had fuel in the tank. Not fast cars, but not unbearably slow either. Especially if left in sport. Very small cabin though. Feels a little tight in the front seat and I can only imagine the back seat. We're a tall family though so ymmv. Good cars though. His was totaled a few months back and he got a 535d to replace it.

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)