Aurora cores

In the Core Generator there are 2 separate Aurora IPs: "GTP Aurora 2.8" and
"Virtex-5 Aurora 3.0". Both work with Virtex 5 LXTs so which one is the best
to use? Presumably the "Virtex 5" version, is this right? What's the
difference anyway?

In my project several dual tiles will be used, clocked via the GTP Dedicated
Clock Routing from 2 sources. How is the clock routing set-up? Once set
it'll never be changed. Do the RefClk_Sel0,1,2 and ClkNorth, ClkSouth bits
have to be set using the DRP?! or is there a simpler way?

TIA

Roger.