Alea Iacta Est

A polymorphed or shapechanged character does not take on average physical ability scores for the race he is morphed into, as polymorph other describes. Instead, he replaces the physical ability modifiers of his own race with those of the new one; inherent, experience and other modifiers still apply, as do his actual ability scores. Any items that can be used by the new form adapt themselves accordingly; weapons will stay at their normal size or change through as many categories as their owner, at the player's choice. Wild magic items work as normal.

Example: Pilios, the insectile human sorcerer, has two pairs of bracers (one for each pair of arms; he has the Extra Item Space feat from Savage Species), and has racial modifiers of +4 Dex, +2 Wis. When he needs to enter towns he uses polymorph self to turn himself into a regular human (sick of people seeing through alter self). Shedding the two extra arms, his first pair of bracers are on his human arms, and work as normal, but the other pair are missing and nonfunctional, to return when he gets his other arms back. His Dexterity is down 4 points (since he is using the human modifier, +0, rather than his own +4), but his Wisdom, not being a physical ability, is unaffected.