Can't help much with the repair (other than it is low pressure so should be easier to repair than high pressure), but as a tall guy with the original model S40 they are small and too low on the ground for a family car but fine for a single guy. Feel a bit sporty (despite slow). We have the early non-US model with MAP ECU which is reliable and very easy to maintain except that only a genuine Volvo code reader works on them. Engine repairs are hard because of limited space.

Something I found out recently is how aircon has evolved. The latest models are much more reliable and efficient in that there is no clutch. They run all the time, just have a linear bypass valve from high pressure to low pressure side (not just on/off but regulating). This means it always keeps things lubricates and should last longer. However I do not know when that was implemented other than some manufacturers started with it around 2001. If you want to comfort yourself that you are buying a good car, it will be an advantage if there is no compressor clutch. You'll see the compressor pulley turning all the time. The modern compressors of the mid/late '90s used on VW and a number of others were troublesome, sometimes lasting less than 2 years. They had a mechanical regulator internal to the compressor but still a clutch. Expensive repairs if you want to maintain the aircon.

My 2L non-turbo struggles with any load, even only 1 or 2 passengers. Driver-only is fine though. Turbo should help. Brakes are great, no excellent.