Hi Patrick, Are you really going to need
SEO - this surely will sell itself with everyone telling friends and buzzing off emails in all directions! I'm ready to sign up for a domain myself! However, from a user's point of view, I must assume you are in the US as your site is ambiguous to people in other countries seeing as you refer to cars that use diesel and 'gas'. Gas is US terminology. I had to search the site to find out if you really meant 'gas' (thinking bottled gas) and found clarification on one page regarding 'gasoline' but no mention of octane levels a vehicle normally used.
This is where more contact information, showing a US address, could have proved useful to the reader but I can understand you not wanting to mention address, etc in case you got flooded with mail enquiries which would be more cumbersome than emails to handle. Mail order though would be another consideration as in many places in the world, rural folk (high users of fuel for vehicles) don't have ease of access to internet banking - in NZ anyway.
Also, more information on City Bank could have proved useful. Can people in other countries sign up for an account with City Bank to help with marketing worldwide?
Finally more information about yourself - especially your trustworthiness eg family man, lived in the same place for years, inventor - whatever!
It sounds an amazing idea but purchasers need to reassured that they're not going to get ripped off. Good luck.