Re: Spider seats
I assume the spider and GTV seats are the same. If so, my local garage advised me NOT to try moving the seats back as they are integrap to the safety of the car.
Like you, I am 6 foot 3 and there is little room to stretch but comfortable enough. I have the cloth seats which found to be smaller than the leather ones meaning there was more room to fit me in.
My seat is reclined and slid all the way back and it is resting on the back seat. I asked the garage about moving the runners back and they said they would not do it but if you want to kill yourself , go ahead. This made me a bit wary about doing the job myself.
Spider seats may be different though.
And my garage could be too scared to try anything new