The disc will only burn as fast as the drive. So there should be no problems using a disc with higher specs than required.
Just in case any Canadians are reading this thread, here is a reliable Canadian source:
http://www.blankmedia.ca/prodsubcats.asp?id=111
Just in case any Canadians are reading this thread, here is a reliable Canadian source:
http://www.blankmedia.ca/prodsubcats.asp?id=111