Thought you were pulling my leg...
There are a zillion ways to voice this- I don't know what your relationship is with the dealer/rep, so this might be too 'stiff'. (Your mileage may vary...)
This letter shall serve to confirm our telephone discussion of March ___, 2002. During our conversation, we discussed my desire to eliminate all additional-cost accessories on my purchase of an 2002 Acura MDX, Model 18_. At that time, you agreed that __[dealername]___Acura would not supply or install any options.
If there are any issues with this understanding, please let me know immediately. I will assume that my MDX will therefore be delivered for a total cost of _____ plus tax, title and documentation fees. Any options installed in contradiction to this agreeement would therefore be at no charge to me.
Thank you for your time and attention in this matter. I look forward to purchasing my new vehicle from ___acura. Should you have any questions, I can be reached at _____.