Rear shock is a Rockshox SID Dual Air - circa 2000. Bought it as a matched par with the front forks. Ride is best described as 'lush'! Very tunable from rolling hills XC style at the lower pressure end through to 'tight' for bombing down tricky drops - not on the Spins though.
Not sure how much carbon is in the Spins - I reckon at best they are carbon reinforced plastic with a fair bit of nylon in there as well. Nice on pavement, but the Crossmaxes / Conti Race Kings go on when I'm looking for some accuracy.
Easton seat post is a Easton EC70, bars are the matched Easton carbon monkeylite risers - both circa early 2000's from memory.
My recommendation (for what it's worth) is definitely get a matched pair of tunable shocks. These things have unmatched ride when you get them tuned. Nothing comes close in terms of smoothness - and I've tried quite a few dualies including Specialized FSR's through to current Epics etc. The MCM's are not light, but then again they are not a race bike either. What they do provide, though is a very comfortable place for ticking over the kilometers and getting amongst the native scenery. I've regularly covered more than 100kms in rides without feeling the slightest bit 'beat up'.
Best of luck with your project.