Hyperspace works great on my SCH-I545 running MK2 with Safestrap. Not much else will work with Safestrap. If you find yourself soft bricked, use the stock image that you flash with Odin. You'll find yourself unrooted; but you can easily root again with the install.bat found in the forums.
Also, Hyperdrive comes with several useful tweaks that not only speed up your device, but also make it look very nice.