The Sparco R100 I have now surprised me.
They are track seats and have thinner padding so can go further back and sit lower (you can raise or tilt them depending on the base you use or spacers).
I really wanted lower seating and more grip which they deliver. I thought I'd be compromising comfort for this by looking at them. After doing two long runs including a laborious trek in and around London including lapping the M25 (don't ask) I've been pleasantly surprised- I found them more comfortable than sport seats.
I was going to get some extra lumbar cushions that they do for them - you can simply velcro them in the back area or even under the knee to 'tilt' but not found it necessary (I've tilted the front of the driver seat by about 10mm using a spacer from
@Southernboy - might try one of
@Pingu new 20mm spacer just to see the difference).
The seats are relatively cheap at less then £200 new. Easy to fit heating pads at around £40 for both seats.
The base however is another £200 :
http://www.sportseats4u.co.uk/index.php?_a=viewProd&productId=5120
However as Tim Beard did, brackets could be made up - a old seat of regular Z3 should make for a cheap donor?
I've also noticed that Konig do seat bases for Z3
http://www.sportseats4u.co.uk/brand...s-bmw-z3-direct-fit-sub-frames/prod_2906.html
They have some good looking seats too:
http://www.sportseats4u.co.uk/koenig-bucket-seats/cat_216.html
If you know what model you looking for then you can keep an eye for a second hand set.
When you down this way next pop in and ave go in my seats, you'll only know by testing a few really.