Just as a heads-up, I bought some Oval extensions to fit into my Profile brackets, and when I received the extensions I was surprised at how short the extensions were. I actually had to lengthen the aerobars with some ghetto copper tubing at the tip where the bar-end shifters go.

So, my advice is that if you can get a chance to actually touch the bars you're going to buy, that would be ideal. But if you buy Oval extensions (I bought the single bend version) you may want to double check with the place from which you're buying as to the overall length of the extensions.