I assume, Urzrkymn, you're referring to the SXX and SXX tc spec, the main difference of these is, as far as I can see is that the tc spec version has a lower motor limit, due to better cooling.
Jayst, the tc spec is not designed for stock and prostock, it's primary design is for mod tourers, hence the lower motor limit, guys like double world champ Marc Reinhard and Ronald Volker used it at last years Worlds in Thailand, and I highly doubt they were running 10.5s!!!
For more details on the SXX check:
TC Spec
Standard Spec
I would get the TC if I could, like you say, you don't want to be shelling out for a new speedo later, if you could get it now!