First of all, I would like to thank @Ursus walking through the negotiation with me while I was at the dealership. It was nice to have an expert to offer advise during the process.
I came in to the dealership offering $414 36/7.5k before tax with 10 MSD knowing they will probably reject my offer but hoping they were desperate enough. They came back at $431 and I knew I could close the deal. But since I was also hunting for E300 loaner at mid 300 range, I was going to walk away and think about it overnight. I also created this post to ask fellow hackers for advise. Then the general manager came over and persuaded me to do the deal and willing to show me the numbers on his PC screen. He mentioned that I do not need to do any MSD and still would get $414 number before tax and I was shocked. Knowing putting down 10 MSD to drop the MF another 0.0005, I asked him to show me the numbers with 10 MSD and he refused to do, saying that it will make the discount less. That made me think that he had no idea about MSD. I later confirmed this with the finance manager as he said it is stupid to do MSD. And he showed me that 24/7.5k miles will achieve the same number of 414. So I went ahead to accept his offer of $414 for 24/7.5k miles as I like to get new cars often. Once I met the finance manager, he put in the 10 MSD and the MF drop to 0.00057, and my payment drop to $373 before tax. I kindly accepted the deal. Below is the final break down of my deal.
Discount $12340 (including $3500 conquest and $750 Costco)
Acqusitioin fee: $995 (They marked it up by $300)
Dealer fee: $199
Zero down. $4500 MSD
Monthly payment of $372.98 before tax
$405.10 after my tax rate of 8.613%
Drive off: $495.10 (1st month payment + $90 plate fee) and $4500 MSD
Additional $200 Costco GC after completing Costco Auto survey.
Dealer had no problem for me to give out their name, but they said they are not going to offer the same deal I got as they “lost” money on the deal. But I guess you never know until you ask. PM me if you want dealer info.