just wondeing i anyone has a polished turbo plenum their willing to sell.....or kno where a how-to is on polishing....
Soak the plenum in a degreaser, scrape off any chunks of debris. Then start with 80 grit and work your way up to 1500 grit (80-100-150-200 etc etc) . Then if you're satisfied with it, take a rubbing compound and a buffing wheel upto it and start with a mild compound and work you're way up to a polishing compound. You could use some rouge style polish, your call. It should take you about 4-8 hours IF you take your time and really apply yourself.