High psi is fine, although you would probably use 300-350 on most carpets.
More important, IMO, is getting the water out of the carpet (along with the dirt
).
For this at least 2 vacs, but there are now a few machines with 3 vacs.
but if you got 2 vacs and 135psi that will work ok, after all that was the bees knees a few years ago.
Less vacs, more dry passes.