Until you know you can trust the company, call their customers. Good companies will give you good customers to call and you can listen and learn a great deal. All companies occasionally have problems. You can find out how they handle these from the people you call. Even their good customers may have had some problems and you can learn how they were handled.
Lead time is really a significant issue.
We often personally deliver our engines to our customers' builders. Experience in this field is a very important ingredient in deciding from who you buy the cobra kit, and ensuring the dream becomes reality and not a nightmare. Calling and talking to salespeople is usually a challenge for the rookie cobra buyer and you don't become a veteran until after you go through the experience and are actually driving one. You will spend hundreds of hours building this dream, so make the most of it by ensuring you don't take on more than you can handle by yourself or with the help of good and reliable friends. Study and study again just how much work you can handle without losing interest.