what are the cranks you're upgrading from? the sugino rd's might not be a significant enough upgrade to seriously warrant 100 dollars. i would recommend watching ebay and craigslist for a used miche primato or sugino 75.

i got my 75 arms off craigslist in terrific shape for 100 dollars even, and things frequently pop up in the trade thread here... if you get the rd's, you will likely want to upgrade them later, and likely end up kicking yourself for not just spending the money upfront...