Does anyone know what the highest top-off price is? I wonder if this is negotiable with gm card?

I'm looking at same deal as O.P. Had $2100 topped-off to $3000 so may be looking to make an offer on this car. Is the supplier price the same as the employee price? ...and did the supplier price just jump up at the beginning of this promotion? In other words, there is probably an extra $800 to negot...