An overabundance of replicas can hurt the market for the real thing to *some* degree, sure. But I would be shocked and amazed if that happens with the 917. It has probably happened some with the Cobra, but I doubt any Cobra owners are unhappy too much since they probably never planned to sell them anyway. There are so many fewer 917's to be had, and it's so not a car that you can drive to Sonic to show off (Sonic is a drive-in burger chain here in the US that often has classic car gatherings on weekend evenings for those that don't know). That said, my monocoque replica will get driven on the street some. *shrug*
Also note that one of Fran's replicas will be better than the real thing in a lot of ways, so it *could* be desirable to even a real 917 owner who wanted to "play" in one, as has been pointed out. For one thing someone with stature should fit in a replica much better. It'll have more room for a second person, should your needs require that. It should also be stiffer and much more crashworthy than an original.
I don't care to even approach the horsepower numbers with mine that a real one had. I had a Lotus Elise (early Federal car) and have experienced tiny, hard to get in and out of, loud, and uncomfortable. I was fairly fine with all of that, but the real problem was it was 200HP at 2000 pounds, and you didn't get the power until high in the revs (and it came on with a switch...ugh). I think 350HP or so with some torque in that same weight will be more than enough fun for any sane person (not that I begrudge those of you who require more...go for it! It's just enough for *me*). I'll get my jollies making the thing handle on track rather than trying to win a long series of drag races rudely interrupted with brake zones and turns.
And if I ball it up, well, it won't have been THAT expensive when you talk about what I have in it.
--Donnie