I wouldn't recomend a 240D or 300D in any kind of traffic. I had a 300D, drove it to Chicago ONCE. It had about 5 seconds of turbo lag... At WOT it accelerated like this: 4mph...6mph...10mph...15 mph...20 mph...40 MPH!!!

Saab 900 turbos can turn in 30 MPG pretty easily. I had a '97 900SE with an MBC (+/- 210 HP or so), that got 30 MPG regularly. Well built, reliable, fun to drive, and cheap. Good support, cheap parts, and they run forever. You can pick up the New Generation 900 (NG900 to Saab folks) in the $3-5k range all day long, and the older ones are dirt cheap. In the NG900 look for an SE model (turbo), for the older ones look for a turbo or SPG.

Saab 9000s are another option, they have the same traits as the 900, but are a bit bigger. Also consider older turbo Volvos, though they are mostly automatics, which are their biggest weakness.

Good Saab sites:
http://www.saablink.net/
http://www.saabcentral.com/forums/index.php
http://saabnet.com/index.html