Cannondale's dropouts were usually setup to 127.5mm width. That is why those of us who have them run 130mm hubs just fine with a little spread upon insertion. I run 10s Campy in both my 1984 ST and my 1985 SR (Crit bike). DO NOT ATTEMPT TO SPREAD THE REAR DROPOUTS PERMANENTLY. And if anyone tells you to do that, stop listening to them and walk away. You can also run older stuff as well. I never had a problem with the ride but I have been on aluminum frames most of my life. And I drive 4x4's and trucks with stiffer suspension so anything else feels mushy to me.
That looks to be a 88/89 vintage but it looks like a shop swapped parts with a frame from something else and a SR300/SR400 series.
Cannondale essentially made two road frames, a touring model and a racing or Criterium bike and differentiated with components. So even if you had a lower priced model it was the same frame as a higher priced model and you could always upgrade based on your budget.
Yes they are worth updating and they handle modern components just fine.