I too was figuring this out, until I found this thread.
Yes, a Torx T5 driver is necessary, but not all drivers are created equal.
And a cheaper driver sometimes performs even better...
Tried two T5 drivers from my local hardware stores. The $2.69 Rubicon performs very well and can provide better torque, so even threadlocked screws can be loosened. Apply some pressure and a bit more counterclockwise torque on the bit, a small "pop" sound means you have successfully broken up the threadlock bond.
The $4.25 Sunflag, however, won't do the trick and the the driver keeps slipping inside the bit too often, wearing out the bit even more. It can loosen non-threadlocked screws, but it doesn't feel good at all and cannot tighten a screw effectively.
I found out that just one of the screws on the 301/303's clip is threadlocked. With the right driver, removal of the clip is a piece of cake and requires no addition heating.
It is important to make sure the screw bits aren't worn out; otherwise, not one single T5 driver will be able to act on the screws effectively, and a pair of small pliers may be needed. When this happens, clamp the pliers onto either one screw and turn counterclockwise. At least one of them should loosen up. The remaining screw (with more threadlocking) should also do the same by wiggling the clip a few times, after which it should come off easily with just any T5 driver.
I was able to remove the clip from the Q3 that has the worn-out screw bits. The rest of my 303/301s also had the clip screws loosened up, but the task was even much easier since all of those screw bits are in good shape.