Writing here, since this thread was super helpful to me! <Thanks again to OP and all the folks who gave in their inputs here>
Went to the CBP Office in Atlanta, was a breeze. They didn't seem to care at all about the TPMS issue, even though i had got after market TPMS installed through Hyundai (i have a Hyundai car). They wanted the 3 forms - EPA, DOT and CPB forms, along with the letter from the manufacturer. They also saw the bill of sale, car title document and valid insurance. Additionally, they then wanted me to get the emissions testing done and local police VIN clearance (probably a Georgia thing). I went back with these 2 new things and then they inspected 3 things in the car - whether the speedo has a miles dial, validated my VIN and confirmed the EPA sticker.
That's it! They stamped my forms and i was on my way! Very cooperative personnel at the CBP. I was a bit nervous walking in but they got it done smoothly!
Moral of the story - avoid the border ports of entry!