I am a bit afraid about this external tool because:
     * We shouldn't assume network access to download it, or ability to host somewhere on-grid.
     * The default setting here can easily break if URL moves or site goes down
     * The tool may come with an incompatible license, or the license could change at some time to be incompatible.

My suggestion is to leverage our ability to execute autotest tests inside a guest.  It's just a few function calls to take care of copying and running the test.  Reports/results/output is automatically gathered into the results of this test.  Also, if you really wanted, you could see about including this 'stress' tool as an autotest-test.  Assuming the license is compatible, it would just take writing a simple control file.

What do you think?