I'd do it ASAP as well. Mine doesn't sound nearly that bad and it's going to nsxrackrepair.com in the next month or so, as soon as the snow flies. Earlier this summer I took the boots off and lubed everything I could access from that point. The squeaking got better, but came back again a few weeks later. This thing could have used a grease nipple apparently.
RHD unit is available from Amayama for US$3,168.84 + shipping
LHD unit is available from OEMacura for US$6,725.44 + shipping
Hard to be sure what the worst that could happen is. Generally, problems with the system that steers your race car have the potential to go very bad, very fast.