If you can run the standard items from Terminal - you do the optimzied ones the same way. Just shut down BOINC, move your current BOINC Client out of the folder it's in, and move the optimized (4.44) BOINC client in. Same for SETI: In the Projects folder is the SETI folder. Open that up, remove the old SETI client, drop in the optimized SETI client and the associated app_info.xml file. Close all the windows, then start up BOINC from the Terminal as normal.
One word of caution, changing out the BOINC won't (shouldn't!!) cause any problems to work in progress, but back up before switching just in case. SETI, however, will delete any work units you have in progress or have downloaded, so run your cache down as close to zero as you can.
One more note: instead of typing "./boinc_4.44_ppcG4superbench" to start it up, I just type "./boinc*" [all without the quotes, of course]. As long as you only have the one file in your Boinc Data file that begins with "boinc_...", it will start up fine with the asterisk acting as a wildcard character.
Changing the MenuBar or BOINC Manager apps to run with the optimized superbench clients is only a little bit more complicated than this, as it needs a couple of extra steps...
beadman