OK here is something I know about. First thing first. Leather seats are painted, I repeat PAINTED.. That laquer is what cracks and looks crappy. Remove it with.....you guessed it......laquer thinner and a cloth.
The porsche seats for my rabbit werent the nicest. Felt like old cardboard. Looked all cracked and nasty. The light linen color hid alot of grossness.
It really does come right off.
Strip the whole seat and it will feel soft and pliable again. Wetsand it with 600 grit paper and it will feel like new.
Kinda bleached looking without all that crap on it
Only when you have removed all the damaged stuff, then you can dye it. I wanted to use a leather dye but the backs of my seats are vinyl so I used colorbond (freaking awesome stuff!) in a late model Mercedes "Java" color.
Here is a before and during shot
They look and feel like new. The "colorbond" stuff from bryndana kicks any SEM or VHT products butt. Not cheap at $14 a can though.