I would run by the local shop and get them installed~!~
The reason I say this...I have ordered some before off internet and Ebay and they were the incorrect stems to fit on bike wheels.
There was a shop here that sold them fo $5 and installed for $5, even if you were not changing tires (included balancing)...now I know he was cheap, but did good work...(this poor fella worked by himself, owned his own shop...and committed suicide in the shop recently so we do not have him any longer)
I got my other set of wheels done at a shop down the road and they were 3 times as much and both had different types of stems...however, neither agreed that the ones I purchased off Ebay should be used.
The sponsors should be able to set you up if you ask them, but keep in mind you're going to have to get them installed at your local shop anyway...
