I can speak from experience. I am polishing my stock 5.0 intake from my 91 mustang GT as we speak. Its a "REAL JOB". If you can take it into someone that has a bead blaster or even a sandblasting shop to take off the powder coating, or even get your hands on some airplane stripper, your off to a good start.
As far as power tools, I have used a few on mine to get me where I am today. I have a Dremel and a mouse sander. I have started with a 220 grit, and when done, will work it down to a 2000 grit mirror finish. I have polished out my 1993 GSXR frame in full, and also done a number of intake plenum covers or "plaques". Its just a matter of patience and time. Its not a weekend project, and may help if you have a spare intake to work on.
Good luck with it!!
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Rob
91 GT Vert | 
How to polish? 
