Looks ain't everything you know. He might be not as attractive as car guy but if you get along really well and stuff perhaps you should give him a go. He may become even more attractive to you as time goes on.
I've only ever been in two relationships (one silly teenager type, and one proper living together type) and in both cases, initially I had "issues" with their appearance, but you're right, people get more attractive the more you like them, which is an interesting thing to happen I think, but I really like it.