Tricky. I suppose it depends on how fast you could 'really' go with a typical load as to whether the ramps would be necessary to keep the shock positioned upstream far enough of the compressor. If it naturally stayed in an OK posuition, no need for the ramps I guess.
A fixed geometry intake will only work efficiently at its design Mach no. At any off-design point, sub-critical or super-critical operation will occur when the oblique shock is not positioned on the cowl lip, because the shock angle depends on Mach no. For aircraft which operate over a wide range of Mach nos, the penalties imposed by a fixed geometry intakes can be unacceptable.
The Tornado was initially fitted with ramps (ie variable geometry intakes) to position the oblique shock wave on the cowl lip of the intake. They were indeed scheduled to work above Mach 1.3. The ramps were a pain in the ass because they frequently leaked hydraulic fluid and it was normally an arduous task to repair. As with everything, the cost of continually repairing the ramps outweighed the benefits of having them so we stopped having them.
Asking a question such as "can the GR4 go supersonic?" generates a million answers, the shortest of which is "yes!"
It will go supersonic in almost any fit at any level with reheat engaged. As has already been mentioned, each store has a mach / IAS speed limit - that does not mean that they cannot go supersonic when strapped to the jet, they just shouldn't.
Obviously, if you had to make a sharp exit, it would be bye bye to the stores and the clean jet would go supersonic and some (but I think that 2.2M is unrealistic at low level).