I need your leather expertise

[Auf los!]

I'm interested in adding or replacing some leather in my full-leather-interior 2001 S. Some of this work I might try doing myself, in other cases I'd like to buy the leather and give it to someone to perform the work. But I need some guidance as to what kind of leather Porsche used in my car. I'm figuring on heading to a Tandy leather store soon, and I want to know what to look for.

If I want to match the leather on my dash and door panels, what are we talking about? Top grain? Full grain? What Porsche installed seems fairly grain-free.

If I wanted to upgrade to what Porsche terms "smooth leather" on some surfaces, or my steering wheel, what is that? Is it really lambskin?? Or is it "garment leather"?

Any advice would be appreciated, thanks.