Lew
Stop trying to hijack this thread!
Obviously each invidual car is going to drive a little different depending upon its fitment--not many originals drive alike from what I've heard from those who have them.
4000s and Kirkhams are going to be just about identical--because they are nearly the same car. Might I suggest this: you're not going to buy one of these simply because of what you read here (at least I hope not).
Contact David and Tom Kirkham and talk to them. Their father's original is parked in the garage right next to the shop. I've sat in it several times, as well as in Tom's own Kirkham and several others (they're building mine to fit my big butt--so I tried them both on to see where feet and arms fall). Other than wear--the interiors are identical, as is the look and feel. I sat in several 4000s down at SAI--you're not really going to be able to tell the difference.
The aluminum twins are lighter than fiberglass cars by a significant amount. There is far more underbody structure to them because, quite frankly, that's what is holding the body up.
We are blind men describing an elephant to you. Go sit and, if possible, drive them. It is a great deal of money (trust me!) and it's important for you to know exactly what you are getting.
