I have spoken with three different Superformance dealers over the course of the past couple of years. I have been quite surprised about their profound ignorance of their own product. While each of them could discuss them on a basic level, none of them had any real knowledge of genuine GT40s, nor could they answer all of my specific technical questions. Yes, they knew the basics, but when I began to delve more deeply, I could see their eyes glaze over, and the tap-dancing begin.
Everybody I know personally who has a Superformance GT40 purchased it from Olthoff, even though none of them are anywhere near him, and all of them have Superformance dealers much closer to their respective homes. Apparently Olthoff is virtually alone in having a deep understanding of what he is selling (warts and all). I'm still a couple of years out from buying mine, but based upon their positive experiences and my lack of confidence in my local dealers, I will almost assuredly buy mine from Olthoff too.