I see guys on ebay selling egr delete plates. Is this a good idea? What benefits can it get me?

Do you mean Blocker Plate. Do it. But you may need a finger stick to stop CEL.

Moved to Fuel System, Air, Exhaust, & Emissions Upgrades

If your referring to the EGR blocker plate, then you will keep the exhaust soot from being recirculated back into the engine.