the best way to rectify your problem is to buy quality media in the first place.
even poor quality media shouldn't be burned more than a notch or two lower than its rated speed or you could introduce even more problems.
i would never burn 16x media lower than 8x. i also wouldn't burn 8x media any lower than 4x. (YMMV as with anything on this forum...)
if you can't get quality burns at slightly reduced speeds, look into firmware updates (if you don't have the latest) or simply purchase quality media in the first place and avoid all of these headaches!