Similar experience on my last purchase. I asked the finance manager the most he would accept with a CC (for points of course) and it was $5K. The issue wasn't only the fee, but as stated above the comsumer protection laws. It left the dealership liable for the CC comapny freezing the funds in case of a dispute if they accepted full paymen via CC. I'll be quite surprised if you can do so, but if you can...go for it!