I've almost purchased the BMW Carbon pieces for the B and C pillar door caps to mask the aging factory finish....I'm just concerned on how flush they fit and if they look out of place on the car itself.

The ones from ebay really look off and aren't precisely cut. Some parts are straight and flush, others are too wide for the part they overlay, or cut at the incorrect angle. Also, ebay kits are 10 pieces total, 5 per side. The OEM BMW kit is a 6 piece kit, 3 per side.