I email the company you listed in your post
http://www.vintageseats.com/seats.htm
asking some questions. Below is the response. They also emailed me a picture of the "R" model seat done in smooth leather with vertical pleating that they made for a 60's vintage Ferrari. IT WAS GORGEOUS. I will try and shrink it to put in the members gallery.
These seats are not cheap. But, looks like they could be very, very nice.
Note from vintage seats:
"The seats are definitely comfortable. Not as much as a
modern Recaro of course but for a period correct seat,
it is pretty darn good. There is some lumbar support
and I have been having my upholsterer use a denser
foam for the bottom cusion, contoured to my specs.
This has helped with comfort as well.
I am located just outside of San Jose, CA
The dimensions of the different model's are all
approximately the same:
Fully upholstered, 20.5" wide, 20.5"-21" tall,
approximately 27"-29" depth depending on upholstered
bottom cusion shape (it project off the front of the
seat). Headrests will obviously add to this.
I have been drilling and tapping the seats to
accomidate New Recaro sliders and bases. The sliders
are generic and offer height and rake adjustment in a
crude way. The bases are made by recaro and they are
the link between the generic sliders and the unique
car's interior seat mounts. Height that is added from
the mounts to the seat with this arangement is
approximately (min) 1.5" If a custom seat base was
fabricated and the car's interior structure
accomidated it, the seat could actually sit below the
plane of the seat mounts.
The approximate distance from the bottom plane of the
seat and the top of the bottom seat cusion (in back)
is approximately 2" (give or take depending on
upholstery cusion design)
I have not yet researched the heating elements for the
seats but it is on my list of thisngs to do. It would
not be a difficult endeavor (i'm making an educated
guess here)
I have attached a picture of my model "R" seat that
was done up in black leather with vertical pleats for
a Ferrari. The cost difference over the German vinyl
is aproximately $650 more per pair. That includes the
headrests.
The ST seat would probably most appropriate for your
use, given the performance potential of the cars
you're dealing with and the high lateral loads they
can generate.
Look forward to talking with you.
Regards, Peter
(408) 354-5420"
Rick