I'm after an a portable connect-to-the-battery air compressor for the Forester's 215/65R16s. It will be for occasional use to raise the pressure back to on-road ~36psi after dropping it to ~30psi for dirt roads. May not even live in the car.
I've done the $20 Chinese cheapie which makes more noise & heat than air (and wouldn't do a football, there was a reason someone gave it to me for free

I'm looking at the "12V 150L/MIN PORTABLE EXTRA HEAVY DUTY AIR COMPRESSOR" from biggerboyztoyz. Any experiences with these, good or bad? Also, how big are they- is the comparable Bushranger smaller?
Oh, and any recommendations on those adjustable tyre let-downers so I can let the pressure out easily.
Thanks,