[Translation from Japanese to English ] Please give me the breakdown of your $795 quotation. How much would it be if...

Original text

＄795の見積もりの内訳を教えてください。
cobra exhaustのみだといくらになりますか？
今ebayで、送料込の＄399で出品されていますが、この値段より安くなりますか？
よろしくお願いします。

Translation / English

Please give me the breakdown of your $795 quotation.
How much would it be if i get cobra exhaust only?
Can you give me further discount on your current ebay price of $399 including postage?
Thank you for your consideration.

Translation / English

Please let me know the details of the $795 quotation.
How much is the amount for cobra exhaust only?
Now on ebay, the price for item is $399 with delivery fee considered. Can you make it lower than this price?
Best regards.