Looks good. We have been re-doing the website at my work, so I will try and give some recommendations from what I have learned there.
Stuff that I like:
The FAQ page gives lots of good info, especially about all the different applications for the duratec engines, I had no idea! The before and after pictures look great also.
As far as recommendations, here are my thoughts:
1. I would make the text in the navigation buttons a bit bigger, as it is kind of hard to read at my resolution (1280x1024).
2. I would add a link to the testimonials site in the navigation bar, especially once you get more added. That would help draw attention to your happy customers and add credability to your services.
3. Consider adding something about a warranty or quality guarantee, even if it is just the warranty on the new Ford parts.
4. I would talk with other companies that offer complementing (intakes, exhaust, etc..) services and parts and add links to them on your website. They might return the favor and add your link to theirs.
Feel free to take or leave any of my comments, but I hope you find some of them helpful.