The rough quote so far is $1400 for all cloth, or $2400 for all leather, so I'm guessing that the final cost will be somewhere in the middle, as I'm going half-and-half. That, though, is for the whole interior: front and rear seats plus door trims. I picked the colours and materials the other night, so it's not too far off, hopefully.
I've got the R32 GT-R rear seats still, so I really should advertise that, and after the rest is sorted, I'll have a pair of Stagea front seats to get rid of too.