-- Last Updated: Feb-12-13 1:32 AM EST --
Tiderace says suitable paddler weight for the Xcite-S is "60-80 kg" which works out to a max paddler weight of 176 lbs. The OP's weight is below that, albeit slightly.
Also, since the Xcite boats are billed as 'rough-water touring sea kayaks' by Tiderace, one assumes you can take a fair amount of gear with you on top of that, i.e. they're all-arounders, not just playboats.
So what it'd likely come down to is, "Can the OP comfortably get his 5'8" frame in there?". The only review of the Xcite-S on Pnet is a 5'9" guy who said the S fits him 'like a glove'.
If the OP digs that kind of fit (and many of us do like 'wearing' our kayaks), then it may well be a good choice. Only way to know for certain is to try one out.
Even if it did wind up being slightly too small or close-fitting, he might like it enough to try the regular Xcite, and fall in love with that.
It's always tough to predict what someone you don't know will want or not want, but there's certainly no harm in him trying stuff out.