I really dig the earlier 240s I have a '79 wagon which has been exceptional. They are, in my experience, bulletproof cars. I am a big fan of the CIS fuel injection system used on these cars, analog over digital any day. Keep in mind I am currently in the process of replacing my fuel distributor so I guess the very thing I liked about my car broke anyway. That and a manual transmission. The electric overdrive is great too, and in defense of my fuel distributor, it had 315,000 miles on it, along with the rest of the car. Even thoutgh Volvo wanted EIGHTEENHUNDERDMOTHERF*^%$INDOLLARS for a new one and Bap/Geon quoted me $775.00, I did get one for free from a junked car my Mechanic had laying around, provided I didn't make him go out into the snow to remove it. Then it probably would have cost more than a new one.
A second difficulty I have had is fuel pumps. I have been through two mains and an in tank pump in 100,000 miles and no , I haven't been using mexican gasoline. as far as I have heard this problem is singular to my experience.
Also look out for drive shaft (read: U-Joint) wear this seems to be common on the older cars especially. Your car has it for sure if it clunks alittle or a lot when you let up on the clutch (think of a train starting up from a standstill). Anyway, that's all I can think of for now. The different dash, the older one, I like by the way. I have a hula dancer in mine and the radio if further from sight so's it doesn't get stolen, this is actually a documented fact.
Good Luck,
David