I picked up a second hand 2007 Jetstream last night for a very good price. Looking at it today all seems to be in good order except the chain, for which I've ordered a replacement.
Going through old threads I can see that my first observation is a general sentiment amongst users: the rear shock is stiff. I don't know anything about shock units, I've never had a FS bike before. Thor used to have a specific replacement for this particular Jetstream model on his site, I don't think it's there anymore. Which implies that after the 2008 frame re-design a different length shock was used, allowing greater interchangeability.
If I wanted to change the rear shock what would my options be? It appears to be 125mm.
Cane Creek used to make a short short one for the bike, but I bought the last ones and they are gone ...sorry ...
(it was an airshock )
there should be some shocks coming from taiwan available in that length .... you might dig a little deeper