Thanks to all you nice people and your helpful advice I was confidently negotiating with car dealers, advising them that paying for the entire car purchase with my Delta Amex was a must, a dealbreaker. Initially ALL dealers said they cap credit card purchases at (variably) $2,000, $3,000 or $5,000. However, being bonus miles-driven, I kept e-mailing dealers. Most came around, but wanted ME to pay the 2% or 3% merchant credit card fee. Finally one dealer (located far away) said he just got approval to charge the full car on my Amex, without charging me the dealer fee. I then had this "ammunition" in negotiating with a dealer nearby (couple miles from my house), who gave me the same deal! Very exciting, and k-ching on the bonus miles! Thank you all again! Tanya