Personally I'd go upgrade as the floppy soggy suspension really annoyed me on my old GL. In the end I coupled that with a set of Spax 40mm springs, genuine Volvo towing shocks, lower strut braces and new standard Volvo bushes.
It handled really well but wasnt a horrible ride either for a daily car either. It took away the wobbliness that the 240 is known for, improved handling but never compromised load carrying either. It made it look like a normal height car to be honest.
My current GLT isn't a daily driver so Ive gone for a much more performance ride which is quite stiff as Ive found out on the short roll to my workshop from the exhaust shop. Comfort doesn't matter on that so it was ok to compromise ride quality for better handling.
For a daily driven 240 I would just go with some good quality lowering springs, some lower strut braces from
WWW.DVS.NET.AU and make sure the bushes are in good condition.