Eric Happy Meal...
Thanks for the good questions. I will try to provide my angle on them and, perhaps some other members will have additional information to help you towards your quest.
1. In a basic sense, all Beetle floor pans are identical for the purpose of building a Dune Buggy. Major variations are if it has link-pin or balljoint front suspension and swing axle or independent rear suspension.
However, cutting up any pan before, say 1968, might be bad for your health as the early restoration people are getting desperate. When I mention that my first Dune Buggy was built from a 1957 convert I get some bad looks, but that was in 1969 and 57's were $100 each. Super Beetle pans are not usable for a Dune Buggy due to the strut style front suspension.
2. If you want to find an already shortened floor pan, I suggest that you shop the different Kitcar sites and even look on ebay under the VW listings. There are also a number of companies building new tube frames for dune buggies. The "correct size" varies slightly due to variations in body design, but is usually 14 1/2" to 15 1/2" shorter than stock
3 & 4. Although the EMPI Imp started it's life right here in beautiful downtown Riverside, CA, I haven't a clue where you could find one today, or if the molds still exist after all these years. There are a number of other "similar" bodies out there. If you should happen to find an original EMPI Imp, I am sure that the price will be substantial.
A good resource for you can be found at www.meyersmanx.com.
Their newsletter always has a number of Manx and non-Manx cars and parts listed. The club is open to all, not just Manx owners. Also check out the classifieds at www.thesamba.com
If you live in SoCal, or can come here, there is always the Pomona Swap Meet, (Next date, March 2nd) where there are usually a number of sellers of the items you wre looking for, from pans and bodies to complete cars, but you had better bring a fat wallet, as Dune Buggy interest (and prices)has soared in recent years.
Let us know more about what you are looking for and I am sure you will get lots of good answers.
1966 MANX SR2 (Karma Coachworks), 1974 VW THING
[This message has been edited by BobMiller (edited 02-17-2003).]