v2.61 admin searches
I think the best way to check if something is faster is to make sure you have a backup and test it (or run your test on a second server).
I glanced at the code of that plugin and I didn't see anything I thought might cause a problem with 2.61, but I'd recommend taking a complete backup just in case! You could try disabling the plugin after upgrading to see if you can get speed improvements without it.
Best of luck!