I have had an aluminium car for a few years now. Cobra not a Spyder but..
And leaving the body in brushed alloy has been no problem.
...it certainly puts an end to that question... "..is that a real one"
i just wipe it over in the direction of the brushed grain using a toweling clothe and WD40. Then wipe it straight off - dry. Cleans up all the road grime and bugs.
Also, depending on price difference, I would encourage this option. Saving on body preparation, paint and spray booth time offsets some of the cost.
.... A nice look. Send me a dialogue message and I can send some photos.
Bernie