I had a 89 944S2 for 12 years. The mechanicals were very similar to the 968. I had to replace a power steering hose a couple of times. The car was prone to leak power steering fluid from that area for some reason.
Just before I sold it I also had an issue with the cam chain tensioner. The tensioner broke off as I was trying to start it one morning. That repair ran me about $4500. It's not an uncommon failure but I don't think there is anything to be done to prevent it. When it's repaired the tensioner mounting point typically gets reinforced so if the car you buy has already had this failure it might be a good thing. I am also assuming the 968 has the same master/slave cam drive that the 944S2 did.
I replaced the clutch once at 65k miles and also replaced the A/C compressor a couple of times. Nothing else major. It had 135k miles when I sold it. I loved that car and hated to see it go. Very easy to control with neutral and predictable handling. If the 968 looks clean with good records, I say go for it.